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Book Review Roundtable: Understanding Proxy Warfare

In this roundtable, we asked our contributors to review Tyrone Groh's book "Proxy War: The Least Bad Option" and to discuss the various aspects of conducting proxy war and what makes or breaks it.

1. Introduction: A Guide to Proxy Warfare

By James J. Wirtz


The use of proxies to harass competitors or to cause trouble in neighboring states is a fixture both in history and in contemporary international politics. Although scholars rarely frame the past in these terms, the French and British used indigenous tribes as proxies to harass their opponents in the New World, which also enabled the natives to pursue traditional vendettas. After being ejected from North America, the French switched to using local colonists to undermine the stability of the British Empire, an initiative that quickly ended London’s unfettered dominion over the New World. In more recent times, the Spanish civil war became a military testing ground as pro- and anti-fascist proxies wielded the latest military hardware and employed novel tactics, while German proxies destabilized Austria, leading to the Anschluss. During the Cold War, proxy warfare became commonplace as North and South Koreans, and North and South Vietnamese served as proxies for their superpower sponsors — or as Albanians harried the Soviets on behalf of their patrons in Beijing.

Today, it is difficult to identify a significant conflict in which some party or another is not acting as a proxy for outsiders. The Houthi movement in Yemen is backed by the Iranian government, which has apparently delivered relatively advanced missile technology to the Houthi so that they can better target cities in Saudi Arabia.1 Unrest in Yemen is often depicted simply as a proxy war between Iran and Saudi Arabia. The Syrian civil war, by contrast, involves several factions that are backed by various outsiders, which has turned a destructive civil conflict into an even more destructive proxy war.2 Indeed, the c­­onflicts in Yemen and Syria probably would have terminated long ago if it were not for support given by third parties in an effort to undermine the regimes in both countries.

In Proxy War: The Least Bad Option,3 Tyrone Groh addresses the past, present, and future of proxy warfare by embarking on an ambitious tour d’horizon on the use of proxies in international affairs. Groh begins his theoretical effort by distinguishing proxy warfare from other types of foreign intervention and influence operations. He also explains the calculations of risk and reward that lead states to use proxy non-state actors to engage in violence to achieve one of four objectives: (1) defeat an opposing government, (2) meddle in the affairs of others, (3) preserve the status quo, or (4) feed the chaos in a targeted state.

Groh also borrows a page from Kenneth Waltz’s structural realism to explain why the incidence of proxy warfare varies as the “polarity” (number of great powers) changes on the world stage.4 Throughout the Cold War, for instance, proxy warfare was common as the superpowers attempted to make inroads in their competitor’s sphere of influence. During the post-Cold War “unipolar moment,” sponsorship of proxies became a relatively rare event, while, today, notes Groh, the use of proxies is on the rise as the world becomes increasingly multipolar. In a multipolar world, more potential sponsors combined with fewer incentives for great powers to bear the costs of international management create openings for the use of proxies to alter the international status quo.

Additionally, Proxy War offers policymakers two bits of practical advice when it comes to undertaking proxy warfare. First, the greater the commonality of interest between sponsor and proxy, the greater the likelihood that the collaboration will achieve stated objectives. Second, the proxy’s dependence on the sponsor is another key to success.

Empirics vs. Theory

Groh is meticulous when identifying the parameters of what he considers to be proxy warfare, leaving the reader to wonder if his parsimony and rigor come at too high a price. For instance, he focuses on non-state actors as proxies. The Cold War cases of Vietnam and Korea are thus beyond the reach of his study. His definition of proxy warfare also stipulates that outside sponsors have to participate in some capacity in the effort on the ground: offering direction, serving as advisors, or providing air or intelligence support. For Groh, these types of direct participation are a necessary condition for proxy warfare. Without participation or direction, aid to an actor in a conflict becomes “donated assistance,” which seems to translate into a situation where clients are free to employ aid as they see fit.

The suggestion that aid would be delivered in such sticky situations with not even implicit restrictions or direction does seem a bit far fetched. In her review of Proxy War in this roundtable, Melissa Dalton sharpens the point by highlighting that, in the case of the United States, strings are always attached to foreign aid. Dalton notes that the U.S. Congress, along with most legislatures in other democracies, demands that the purpose of aid be stipulated, although she admits that things can become somewhat murky when dealing with non-state actors. If one were to add in the U.S. requirement to conduct “Leahy vetting” — the need to guarantee that aid recipients are not guilty of gross human rights violations — then Dalton is well justified in noting that the distinction between proxy warfare and donated assistance is largely moot, at least in the United States. Groh’s definition of proxy warfare might be so highly specific that it excludes carte blanche interventions that rarely, if ever, exist in international affairs.

Groh also explores the issue of proxy warfare mostly from the perspective of the principal, not the agent. His guidance on the conduct of proxy war, for instance, is directed at the sponsor, not the proxy. Nevertheless, the principal-agent relationship embodied in proxy warfare is both dialectical and asymmetric in virtually every respect, and as Erica Gaston highlights in her review essay, Groh does not account for “agency” in proxies. In most cases, it is hard to imagine that common interests extend much beyond having a common enemy. When circumstances change, the client might decide to press the bounds of that principal-agent relationship to the point of failure. Indeed, David Lake has recently highlighted the inherent and inevitable divergence of interests in similar patron-client relationships. Lake notes that increasing client dependence on sponsors not only creates a moral hazard but impedes the ability of the client to make deals necessary for ultimate political success.5 The more the agent is dependent on the principal, the less likely the agent is to have the capability and incentive to successfully create political deals that satisfy local concerns, which rarely correspond to the patron’s wishes. Gaston throws even more cold water on the possibility of maintaining coherence and control by highlighting the sheer complexity of proxy warfare involving non-state actors, which can accrete or shed objectives and members quickly. Non-state proxies can be rather slippery characters.

Groh’s case study of the American use of Hmong tribesmen in Laos to wage a proxy conflict against Hanoi during the Vietnam War illustrates how ephemeral common interests between principal and agent can be in practice. The Hmong were mountain people with little affinity for outsiders, a disdain that was reciprocated by their countrymen living in the lowlands. Nevertheless, the Hmong hated the North Vietnamese and Pathet Lao (communist) rebels who operated in their general vicinity and were happy to take American aid to attack communist units who strayed into their mountains. For the Hmong, however, no good political solution to their military and cultural predicament really existed. They were not only incapable but were also unwilling to run a Laotian government and they could not stand up indefinitely to growing pressure from North Vietnam. Paradoxically, the more the Hmong conducted successful conventional military operations, the more vulnerable they became to communist countermeasures, leaving their American sponsors to urge caution and a return to the mountains and guerrilla operations. The Hmong were eventually decimated in conventional engagements that Americans encouraged them not to undertake. If there were common interests between the Hmong and the United States at the outset of their proxy relationship, those interests were corrupted over time. In the end, the Americans lost their proxy as the surviving Hmong lost their way of life.

Sara Plana also takes exception to the way Groh frames proxy warfare as the “least bad option” available to policymakers because his perspective underplays myriad non-kinetic ways that states can influence events in foreign lands. For Plana, Proxy War artificially limits policymakers’ choices to doing nothing, engaging in proxy warfare, or engaging in direct military intervention. Instead, she suggests that proxy warfare appeals to policymakers when other less drastic measures have failed to alter situations to their liking. One might also add that some of the proxy warfare objectives identified by Groh, especially “feeding the chaos,” are not in keeping with the best traditions of public policy or diplomacy. Indeed, if this is the best objective policymakers can devise, it might just make more sense to simply do nothing. In any event, trying to maintain a coherent policy and control proxies amid the chaos of proxy warfare might, by definition, be an impossible task.

As this brief introduction suggests and the reviewers confirm, Proxy War has provided theorists with a valuable framework to better understand an important and increasingly common form of foreign intervention. Groh has not supplied us with the final word on the subject, but he has offered scholars a logical way to think about proxy warfare, sparking the lively and constructive commentary that follows.


James J. Wirtz is dean of the School of International Graduate Studies at the Naval Postgraduate School in Monterey, California.


2. A Good Place to Start

By Melissa Dalton


U.S. rivals are shaping the international security environment to their advantage, while the United States is caught on its back foot. These adversaries, which include China, Russia, Iran, and North Korea, are leveraging a range of coercive tools to undermine U.S. interests in a space outside day-to-day statecraft and open warfare that some analysts call “the gray zone.” These challengers are using tools that include information operations, political coercion, economic coercion, cyber operations, space operations, provocation by state-controlled forces, and proxy war, often in combination.6

Proxy support includes the direct or indirect use of nonstate and parastate groups to carry out militarized intimidation or control territory in order to exert influence or achieve specific security or political outcomes. Contemporary examples include Iran’s use of proxy forces to build influence in or destabilize key areas of the Middle East (e.g., Iraq, Lebanon, Syria, and Yemen), such as local governance and security structures, and limit U.S., allied, and partner operational access in these areas; Russia’s use of proxies in Ukraine to undermine Ukrainian institutions and enable the annexation of Crimea; and China’s use of commercial fishing vessels to challenge international maritime access.7 These state actors can use proxies in this manner with few costs, although they must calibrate their employment to avoid the risk of escalation. Short of rebukes at the United Nations or in the form of a demarche, they face little blowback to their reputation or accountability.8

The United States is quite active in the gray zone, having long leveraged many of the tools commonly used there, including the use of proxy forces in places like Afghanistan, Niger, Laos, and Syria. However, the United States incurs higher risks and costs in using these approaches, as it must do so in accordance with its principles and values, while remaining accountable and transparent to taxpayers and achieving U.S. strategic aims. As a democracy, the United States must provide a higher burden of proof for why its proxy force activities — whether proactive or reactive — are necessary. Indeed, there have been increasing calls from Congress for caution and circumspection in the use of proxy forces, as well as greater political and public oversight and scrutiny of these activities.9

As the United States seeks to compete with rivals that don’t play by the same rules, there will be a strong impulse among U.S. policymakers to shed or bypass accountability checks. In fact, these are the very situations in which the United States should distinguish itself from its rivals, harnessing its principles of transparency and accountability as an asymmetric advantage. The values-based rationale for such an approach centers on doing what is right in concert with good governance and international humanitarian law and human rights. This coincides with an interest-based rationale that being more accountable is good for American institutions, increases both strategic and fiscal return on investment, and attracts allies and partners to want to work with the United States. Such an approach yields balanced and principled policymaking.

Yet, despite congressional oversight of the proxy activities that are being conducted by the intelligence community and the Department of Defense, the United States lacks a coherent policy framework for evaluating choices related to supporting proxy forces that goes beyond assessing operational risk or achieving short-term objectives. It is past time for the U.S. government to develop a framework to determine where specific proxy activities fall on a spectrum of engagement in order to better calibrate relationships with security partners. This spectrum would range from transactional opportunities, to operational partnerships, to partnerships that may present opportunities for long-term investments in subnational governance, with some partnerships fitting multiple categories.

This framework would also address a series of key questions: Should the United States engage with partners for their transactional value, and at what point does such an approach lead to diminishing returns or undue risk to related U.S. interests and values? How can the United States ensure that it achieves its desired outcomes in the support of a proxy force in a principled way? If the nature of a proxy relationship is purely transactional, what kind of leverage can the United States bring to bear on the proxy to shape its choices and behavior, including with regard to how that force treats the civilian population?

A Good Foundation with Some Cracks

U.S. policymakers often grapple with these types of choices as an afterthought or when facing a crisis. But for those looking to get ahead of the curve, Tyrone Groh’s new book, Proxy War: The Least Bad Option, proposes a framework that could fill the aforementioned policy gap, at least in part. Groh explains that policymakers are often confronted with what they view as a binary choice of not intervening in an external conflict, and thus suffering potential blowback at home and abroad, or intervening and risking failure or being perceived as too aggressive or unconcerned about civilian casualties. He asserts that proxy war may be the least bad option between these seemingly binary choices.

Groh sharpens the boundaries of proxy war and suggests a four-part typology for policymakers looking to engage proxies in different ways. The first is “in it to win it,” in which the intervening state has vital interests in the country in question and so the outcome of the conflict matters greatly and therefore more resources should be expended there. In the second, what Groh calls “holding action,” localized threats to the intervening state’s vital interests are low but the threat may spread to the region, making nonintervention impossible. Localized threats also often extend the conflict. The third is “meddling,” in which the intervening state may want to alter the status quo. While intervention by using a proxy contributes little to the intervening state’s vital interests, it can enhance the state’s position with low costs to prestige and with fewer capabilities deployed on the ground. Finally, the fourth type of proxy warfare is “feed the chaos.” In this scenario, the intervening state does not need concrete military successes to secure its vital interests; however, by prolonging violence, it can prevent the opposing side from increasing its own power and influence.

Although this framework provides a useful foundation, it is lacking in three key areas. First, Groh asserts that using proxy war as an indirect approach to intervention requires considering two factors: the proxy force’s utility — can the proxy provide the ability to intervene — and its efficacy — if supported, can the proxy achieve the desired outcome. Although Groh does highlight the potential for a principal-agent dilemma and how that might undermine proxy force efficacy, particularly if the intervening force and the proxy force have misaligned objectives, he misses a third critical element: legitimacy.

Proxy force legitimacy is arguably just as important as utility and efficacy, in terms of its relative authority in the territorial area of control, and relatedly, its resonance among the local population and governance (or even informal governance) structures. Without this key ingredient, even a militarily capable proxy force will not have staying power to connect the intervening state’s short-term objectives to long-term goals — even in the “feed the chaos” scenario, the most Machiavellian of Groh’s proxy war types.

Second, in addition to overlooking legitimacy, Groh is overly bullish on the concept of control. He assumes that if the intervening state sustains the coherence of its policy as conditions on the ground change and maintains “near-absolute control over proxy actions,” then  “proxy war can provide a useful and efficacious option for intervening states, “even under suboptimal conditions.”10 However, maintaining near-absolute control over a proxy force is nearly impossible for any intervening force, and especially that of a democratic government. Even in scenarios where the United States is fully partnering with a proxy force in combined operations, and the proxy force has no other options for obtaining arms, funding, or logistical support, the proxy force can always subvert the donor, avoid taking actions that run contrary to its own interests, or be pulled in another direction by countervailing interests. For example, as dependent as the Syrian Democratic Forces (SDF) were upon the United States, the threat of a Turkish intervention in northeast Syria put pressure on the core Kurdish element of the SDF, pulling attention and resources periodically away from the coalition effort to counter the Islamic State insurgency from 2018 to 2019. Ultimately, U.S. failure to understand Turkey’s motivations and to factor them into plans for its counter-terrorism relationship with the SDF led to the collapse of the U.S.-SDF partnership after Turkey’s intervention in October 2019.11

Third, in the course of framing his recommended approach to proxy warfare decision-making, Groh creates a distinction where one should not exist between “donated assistance” and proxy warfare. Like supporting a proxy, Groh contends that donating assistance provides a middle ground between action and inaction. But he defines donated assistance as providing resources without intending to direct the action of the local actor. Yet, in the case of democracies such as the United States and many of its allies, this is an artificial distinction. The United States still has legal, policy, and moral responsibilities in providing donated assistance to partner and allied countries or nonstate actors in ways that America’s competitors do not. Due to both statute and policy, the United States must link its “donated assistance” — presumably training, advising, equipment, exercises, institution building, and educational opportunities provided by grant-based assistance — to a specific purpose of shaping partner behavior and the environment in which the partner is operating. Steps both the State Department and Defense Department are taking to improve planning, assessment, monitoring, and evaluation of security sector — or “donated” — assistance will only strengthen these policies and processes.12 However, these policies and processes are weaker when it comes to assisting nonstate actors. In practice, donated assistance and proxy support are often provided in the same regions or even to the same groups, sometimes with little coordination, indicating the need for a greater linkage in the policy frameworks and accountability mechanisms of the two efforts.

Groh’s framework for proxy warfare is a useful starting point for strengthening the strategic rationale for supporting proxies. For application in U.S. policy, it ought to be connected to a broader debate and approach that weighs proxy legitimacy, the relative leverage the United States will have with any proxy force, and the range or types of interventions the United States may be undertaking with local forces, including security sector assistance. This broader and principled approach will enable the United States to play to its strengths in the growing competitions with its rivals.


Melissa Dalton directs the Cooperative Defense Project and is a senior fellow and deputy director of the International Security Program at the Center for Strategic and International Studies (CSIS). Prior to CSIS, she served at the U.S. Department of Defense for 10 years.


3. Out of Control: When Proxy Warfare Doesn’t Play by the Rules

By Erica Gaston


Proxy warfare has gained renewed attention in recent years, both by scholars and policymakers. Andrew Mumford has argued that resorting to proxies has increased so much that proxy interference has become the “norm” since 1945.13 Work by Mumford and other scholars has suggested that factors like declining superpower dominance, a more charged but interdependent and interconnected world, and the rise and potency of non-state actors and asymmetric threats, have made indirect or proxy intervention more attractive than ever.14 Nowhere is this on greater display than in the Middle East, which has become, as Seyom Brown has described it, a “cauldron” of proxy warfare.15 There are multiple reasons why the Middle East is an epicenter for proxy war: International Crisis Group President and CEO Robert Malley has pointed to the fact that the Middle East is “the world’s most polarized region and, paradoxically, its most integrated.” He argues that this combination, along with “weak state structures, powerful nonstate actors, and multiple transitions occurring almost simultaneously,” increases volatility and makes the region prone to intervention.16

The sheer number of potential proxies and patrons creates many opportunities for proxy relationships to emerge in the Middle East. Whether in Syria or Yemen, in Iraq or Lebanon, numerous would-be patrons — sometimes doubling as proxies — are present, including Iran, Saudi Arabia, the United Arab Emirates, Turkey, the United States, and Russia, among others.17 Moreover, within these fragmented landscapes, sub-state domestic parties or forces, or non-state actors — sometimes transnational, sometimes purely domestic in nature — often wield as much influence as the host nation or external actors, and may take on relationships of support and coercion with smaller forces or groups that mimic strategies of proxy warfare.18

Such dynamics have made proxy warfare more likely, but they have also made it much harder to identify and define. With many more potential patrons and proxies, and complex, constantly-shifting dynamics, it is difficult to know who is playing whom — who is the proxy and who is the patsy. During the Cold War, analysis of proxy war was heavily state-centric and was viewed through the binary lens of U.S.-Soviet competition for influence.19 Post-Cold War analysis of proxy warfare has given greater attention to the way that states might use rebel or insurgent groups or other non-state actors as surrogates or proxies to exert influence in another state.20 However, the difficulty of pinning down these more fluid actors and relationships has meant that assessments of proxies in these environments often devolve into unanswerable questions about the nature or level of aid given to a proxy, whether an understanding or agreement exists between the proxy and patron, as well as how much control the patron exerts versus how much independence the proxy has.21

The challenge of identifying what constitutes a proxy relationship is an issue that is not limited to academic debate. As tensions escalated between the United States and Iran in the second half of 2019, the question of whether the Houthi regime in control of northern Yemen, or the Shi’a militias leading the official Popular Mobilization Forces (the Hashd ash-Shaabi) in Iraq were Iranian proxies became central to U.S. threat perceptions and responses in the region.22 Were these groups under sufficient Iranian control and direction such that any acts of aggression by them — which included sabotaging oil tankers or facilities, cross-border attacks on Saudi Arabia, and missile launches and other threats against American facilities in Iraq23 — should be attributable to Iran?  There is broad agreement that some Iranian support exists for these groups but that they also have substantial autonomy, as well as their own robust grievances against the United States and its partners in the region (Saudi Arabia and Israel are the most notable).24 Moreover, however closely the United States interprets this proxy relationship to be, there is the question of how to respond. Given U.S. reticence for significant troop deployments in the Middle East, should America be focusing more on cultivating its own proxies in the region?

Tyrone Groh’s new book, Proxy War: The Least Bad Option, wades fully into this debate, contributing additional nuance and precision to the overall discussion of proxy warfare and to the decision-making process for states attempting to take that route. Groh does not delve into the ongoing Middle East proxy dynamics per se, but given that his book is openly aimed at enabling U.S. policymakers to evaluate when proxy warfare might work, it is a timely injection into America’s policy dilemma in the region. Groh’s starting definitions and theorization of proxy warfare make a valuable contribution, offering the possibility of further developing the conceptualization and understanding of proxy warfare. However, he places a high emphasis on state control, which feels out of step with the messier and more fluid proxy dynamics described above, and with the challenges that policymakers are likely to face in identifying and responding to proxy threats in these environments. Had Groh taken an overall less state-centric approach and instead paid greater attention to the agency and initiative of so-called proxies, he might have strengthened the immediate policy relevance of some of his arguments.

A Call for Coherence and Control Amidst Chaos

Groh is not a champion of proxy warfare — he introduces and closes the book by warning against the overly enthusiastic embrace of “by-with-and-through” strategies that are popular in Washington. He also argues, however, that it is likely that “a proxy war policy will go ahead despite suboptimal conditions.”25 Groh’s analysis of structural factors in the international system suggests that in a quasi-unipolar (trending toward a multipolar) system, there are increasing incentives for states to resort to indirect warfare as a way to reduce their culpability and manage unwanted escalation. Groh recognizes that the temptation to engage in proxy warfare may be inevitable, but seems to wish U.S. policymakers would be more calculating about when to cultivate proxies and when to cut them off.

Control is an important element in Groh’s analysis. The level of control over proxies and the hierarchical relationship that this creates is central to his litmus test for when a proxy relationship exists. He differentiates relationships where control exists from instances of “donated assistance,” wherein a state “provides an indigenous third party with the means to fight but cedes all control to the third party.”26 Control is also central to the main policy takeaways of the book. In Groh’s view, control both of the proxy and of the policies governing a proxy strategy is the only way that a proxy warfare strategy can work. Proxy warfare can only be a “useful and efficacious option … so long as the intervening state sustains the coherence of the policy as conditions change and maintains near-absolute control over its proxy’s actions.”27 The main empirical chapters of the book — case studies on America’s proxy war in Laos, South Africa’s proxy war in Angola, and India’s proxy war in Sri Lanka — are focused on illustrating how the degree to which maintaining policy coherence over time resulted in more or less successful proxy policies.28

These control dynamics are an important part of analyzing any proxy relationship, and coherence is certainly to be wished for in management of any policy. However, in developing and applying these theories, Groh might have done better to focus less on the attainment of control and more on the structural elements and factors in current proxy contexts that are most likely to frustrate decision-makers’ efforts regarding coherence and control. Changes in geopolitical dynamics and in internal conflicts have led to more fragmented, fluid, and fluctuating dynamics surrounding proxy warfare.29 These elements may incentivize intervention, but they make it more challenging for any external actor to maintain a coherent policy and exert control over a proxy. As Groh himself identifies in his analysis of the international system, the current quasi-unipolar moment (as he describes the post-2001 international structure) gives regional powers a sense of “greater flexibility to intervene and expand their spheres of influence.”30 This more competitive and “polyarchic” dynamic, as Seyom Brown characterizes these same dynamics, incentivizes greater resort to proxy warfare, but also creates greater uncertainty and flux within that proxy competition.31

The rising significance of non-state actors in these environments adds to this complexity. Brown argues that the “relative rise in power of the non-state actors, and the volatility of their relationships” are essential characteristics within the current polyarchic moment, and contribute significantly to greater fluidity and uncertainty in the international system.32 Malley observes similar dynamics, noting that

Some states are more akin to nonstate actors: the central governments in Libya, Syria, and Yemen lack control over large swaths of their territories and populations. Conversely, several nonstate actors operate as virtual states.33

Such powerful non-state actors and state weakness, in a region that is as interconnected as it is polarized, can both incentivize and facilitate external intervention, contributing to greater combustibility and flux, Malley argues. He points to a number of pan-regional fault lines — from pan-Shi’ism and Kurdish nationalism, to the Saudi-Iran and intra-Sunni rivalries best symbolized by the diplomatic fall-out with Qatar in 2017. With microcosms of these fault lines manifesting in localities and subgroups across the Middle East, “local struggles quickly take on regional significance—and thus attract weapons, money, and political support from the outside.”34

Across the Middle East, these non-state or sub-state actors often control significant territory, have an equivalent or greater level of coercive or military power than the state,35 and may have the capacity to run their own proxies.36 In Iraq, for example, stronger non-state and sub-state actors, such as the dominant Popular Mobilization Forces, leading political parties or actors, and even transnational actors like the Kurdistan Workers’ Party are coopting or supporting smaller forces or constituencies to gain control or counter rivals in strategic areas.37 Kim Cragin has coined the term “semi-proxy warfare” to characterize similar non-state or transnational actor-dominated proxy dynamics in Syria.38 These sub-state or non-state actors are often in a better position to control and manipulate the situation on the ground than external actors, and are able to act alternately as spoilers or proxy enablers.39 Both sub-state patrons and proxies may also receive support from external actors, creating a layered proxy competition that makes it more difficult for an external actor to understand its proxies in the way Groh recommends.40

The challenges of information asymmetry and not fully knowing proxy intentions are certainly not new — these are classic dilemmas within proxy warfare and central issues within principal-agent theory.41 Nonetheless, the multiplicity, volatility, and complexity described above are the sort of conditions that exacerbate information asymmetries. Principal-agent theory also suggests that proxies may be more unreliable when they have multiple potential backers they can turn to, because their options for defaulting or shirking their duties increase.42 As a result, the situations in which U.S. decision-makers might be most likely to consider a proxy warfare strategy are often a worst-case scenario in terms of having some fidelity over proxy motivations and relationships. Overall, the greater influence, agency, and independence of these non-state and sub-state elements, and their more fluid and charged competition with each other, challenge the ability of external actors to successfully manage proxy strategies and maintain control — the issues of central concern in Groh’s book.

Clinging to State-Centric Analysis, and Ignoring Proxy Agency

In theory, Groh is not neglectful of the changing dynamics described above. He initially frames the book as focusing more on non-state proxies, the motivations of the actors involved (proxies or patrons), and the local dimensions of proxy conflicts, all of which are elements Groh argues previous scholarship has neglected.43 He also discusses proxy warfare from the perspective of principal-agent theory, focusing mainly on how self-interested agents may thwart a patron’s interests.44 Despite this encouraging initial framing, Groh’s structural analysis, which is intended to provide the framework for the rest of the book, focuses almost exclusively on how changes both in power balances between states and the structure of the international system shape the resort to and nature of proxy intervention. Groh largely omits the influence of sub-state or non-state actors on these international system dynamics, and his subsequent case studies follow suit. His detailed case studies focus on pre-2001 conflicts (Groh notes that this is to enable access to more complete and rigorous data). This means that although Groh’s theoretical framework does recognize the 21st-century dynamics that affect proxy warfare — increased interdependence and multipolarity, and the rise of non-state and sub-state actors — his case study selection removes these dynamics from the core applied analysis.45 In addition, although non-state actors are present in these case studies as proxies, they represent little more than objects of the patron-state’s will and intentions.

The same issue prevails in Groh’s limited examples from the post-2001 period. In his discussion of the relationship between Iran and the Houthis in Yemen, for example, Groh dismisses evidence and analysis by Yemen experts suggesting that Iran’s support is not conclusively a proxy relationship.46 Apart from an endnote in which he recognizes Thomas Juneau’s point that the Houthis dismissed Iranian warnings not to seize Sana’a in late 2014 (thus implying that Iran lacks full control over them), Groh offers no discussion of whether the Iranians have sufficient control to meet his own proxy definition. Nor is there any discussion of the Houthis’ own long-standing capacity and interest in both initiating and sustaining a civil war on their own initiative, as well as in attacking Saudi targets — a level of agency that would seem to undercut the sort of hierarchy that Groh posits for a true proxy relationship.47 Instead, Groh seemingly settles the question of whether the Houthis are a proxy with a very Cold War-esque analysis of Iran’s relative power and realist spoiler aims in the international system. The Houthis are viewed only as an object of Iran’s proxy motivations, and the real challenges or nuances of the case — both as they relate to Groh’s definitions and to those trying to counter the Iranian-Saudi influence in the Yemeni conflict — are elided.48 Groh’s unwillingness to look under the hood, so to speak, of the Houthi-Yemen case study is a symptom of a larger missed opportunity in the book. Despite proposing interesting theoretical conceptions that take proxy warfare analysis beyond purely state-centric assumptions, he ultimately fails to deliver the same consideration in his applied analysis.

Considering how Houthi autonomy and independence test proxy definitions might also have offered the opportunity to unpack one of the more promising conceptual contributions of the book — that of “donated assistance.” In the initial theoretical chapters, Groh argues that many situations currently described as proxy warfare are in fact situations of donated assistance — a new concept he introduces to describe situations in which states try to exert influence through a surrogate, and provide some support toward that end, but lack the directive control and even the intent to fully control outcomes.49 Given the range of relationships and intervention mechanisms that tend to be folded into the term “proxy warfare” — at least in popular treatments — the idea of creating a separate definitional category that denotes a relationship of influence, but one that falls below the proxy threshold, is a potentially useful contribution.  However, the value of this contribution is somewhat limited by a muddled and often absent application of the concept, which all but drops out of the analysis after chapter 3. The few examples Groh offers raise more questions than they answer. For example, his treatment of Pakistan’s running of the Afghan mujahedeen in the 1980s is an example of proxy warfare, but America’s financial support to the same mujahedeen is “donated assistance.”50 Groh does not make clear why he is making this distinction, which would seem important before dismissing what is often considered one of the classic examples of U.S. proxy warfare.

Considering Iranian support to the Houthis as a form of donated assistance would not only have been a better match to the available evidence, it would also have opened up Groh’s analysis to a probe of indirect intervention dynamics in the much more widespread situations in which the patron exerts less control over the proxy. This is a larger missed opportunity in the book. As the prevailing discussion suggests, the current dynamics in places like the Middle East make indirect intervention more likely, but they also make the sort of full control and hierarchical relationship that characterizes Groh’s definition less likely. This does not mean that external intervention is not present. It is a very real dynamic underlying Iranian assistance in Yemen, as well as external support in numerous other places. For example, the United States does not currently have clear proxies in Iraq, but it gives significant levels of financial assistance to and has clear tactical relations with a number of Iraqi forces and actors — including parts of the Iraqi state, the main Kurdish parties and forces,  and Sunni and minority forces — that might constitute donated assistance as Groh defines it.51 Although they are not proxies, the United States nonetheless frequently tries to leverage or lean on these relationships to counter-balance Iranian influence in Iraq and to advance U.S. interests vis-à-vis Iran in the region.52

The same is true of certain donated assistance relationships on the other side of the proxy equation in Iraq – those involving Iran. While Iran’s support to some of the dominant Iraqi Shi’a militias in the Popular Mobilization Forces likely approaches a proxy relationship, Iran simultaneously has a wide range of assistance relationships across the Iraqi political spectrum, including with Sunni and minority leaders and forces and the two main Kurdish parties — the Patriotic Union of Kurdistan and the Kurdish Democratic Party — that are closer to donated assistance.53 Even if these groups are not as ideologically close to or as strongly influenced by Iran as some of the Shi’a Popular Mobilization Forces groups, where the Iranian and Iraqi actors’ interests do align Iran has been able to leverage these relationships to further its interests or to undermine the interests of the United States.54 In fact, this strategy of having a range of different relationships and varying levels of influence has worked well in the fluid and highly fluctuating dynamics within Iraq, allowing Iran to have a more significant influence than it would have with its true proxies alone.

These donated assistance relationships may not be proxy relationships, but they cannot be divorced from the larger U.S.-Iran proxy competition. Viewed this way, donated assistance is a separate policy option within an overall framework of surrogate competition and indirect intervention and influence. It is a strategy to try to exert some influence with decreased control, which, given the increasingly complex dynamics in the more fragmented Middle East polities, may be all that is possible. Or it may simply be the best way to invest in a more fluid and frequently upended situation.


Groh’s book offers many valuable contributions to the discussion and theorization of proxy warfare. Some of the concepts he introduces, like donated assistance, have the possibility to further develop and meaningfully expand the scope of understanding of proxy warfare. Although his system analysis is, in this author’s view, too state-centric, his overall discussion of how factors like greater interdependence, overlapping but conflicting interests, and an increasingly de-monopolized balance of power may increase incentives for indirect intervention is nonetheless a helpful foundation for analyzing current proxy warfare dynamics.

However, by giving greater attention to the interior dynamics that shape many proxy contexts and to the agency and initiative of so-called proxies, as well as by taking an overall less state-centric view of the patron side of the relationship, Groh might have strengthened the immediate policy relevance of some of his arguments. The promise of the concepts and criteria he introduces would have come through more if they had been applied to the full range of messy realities and nuanced relationships that comprise contemporary proxy warfare. Had he done so, his book might have contributed more guidance that would allow policymakers to deal with situations in which coherence and control is not possible. It might have also forced Groh to consider more fully the places where proxy warfare is inadvisable and de-escalation is in order. For a book that opens and closes with an admonition that proxy warfare is not a panacea, and in most cases not the right solution, we are left with few messages about what policymakers should do in lieu of turning to proxies in these situations.


Erica Gaston is a conflict analyst and human rights lawyer with more than a decade of experience exploring security dynamics, governance, and rule of law issues in Afghanistan, Iraq, Yemen, Syria, Pakistan, and other countries. Her recent work focuses on local, hybrid, and sub-state forces in Iraq, Afghanistan, and Syria, and changing legal norms and practices surrounding proxy and surrogacy dynamics. She is currently a non-resident fellow with GPPi in Berlin and the New America Foundation in Washington, DC, and a PhD candidate at the University of Cambridge. 


4. Proxy War: The “Least Bad Option” or the “Second-to-Last Resort”?

By Sara Plana


Research and commentary on U.S. national security is overflowing with discussions about whether the world may be entering a new Cold War: In what ways will competition between powerful states be similar to or different from the U.S.-Soviet contest? Is the historical analogy still relevant, or do we need a different framework?55 Within this active debate, the question of whether states will embrace proxy warfare — as both the United States and the Soviet Union did — and the implications for peace and security if they do, has gained traction among analysts and policymakers. Yet, the subject thus far has received limited attention from the academic community.

Enter Tyrone L. Groh’s ambitious book, Proxy War: The Least Bad Option. Groh’s work tackles two crucial questions on the minds of policymakers grappling with the future of interstate competition: why states choose to support non-state armed groups abroad, and how these surrogate strategies can be effective for these intervening states. Through his logical argumentation on both counts, Groh makes a much-needed contribution to the understudied phenomenon of proxy warfare.

Where Are the Non-Military Options?

Groh’s central argument is foreshadowed in the book’s title: A proxy policy is often a state’s “least bad option.” Through analysis of 11 case studies, three of which he isolates for close examination, Groh contends that states turn to foreign surrogates when they find themselves between a rock — the costly option of direct intervention — and a hard place — the costly option of non-intervention — but do not want to give up on a particular objective in a country.56 For each case that he examines in depth — American intervention in Laos, South Africa’s support for armed groups in Angola, and India’s support for Tamil rebels in Sri Lanka — he outlines the different barriers that each state’s decision-makers faced with regard to non-intervention and direct intervention, forcing them to settle on a proxy strategy.

Most existing research on what motivates states to engage in proxy warfare agrees with Groh that proxy policies are the result of states weighing the domestic, international, or reputational costs of direct intervention with the domestic, international, or reputational costs of not intervening, and choosing the lower-cost strategy of proxy warfare as a compromise.57 Analysts like Groh see only three options: not intervening, intervening directly, or intervening indirectly. This is an incomplete list, however. It presents a limited, false choice between a military-style intervention or no intervention at all, when in reality a policymaker’s menu also includes non-kinetic means of intervention, including diplomatic or political interventions, economic instruments, or threats of military force.

Failure to look at non-military options leads Groh to wrongly conclude that indirect intervention is the only rational option when direct intervention and non-intervention are too costly. For example, in his discussion on the effect of domestic constraints on state decision-making, Groh claims that proxy warfare can be the solution to the dilemma that decision-makers face in “attempt[ing] to manage the desire to do something with the desire to remain, or at least appear to remain, uninvolved or minimally involved.”58 The natural next question, however, is why a state would select a proxy warfare strategy rather than other minimally-invasive but non-military approaches, such as sanctions or diplomatic intervention. Proxy warfare is not the only possible “stopgap measure” until “decision makers figure out what they want to do.”59 In fact, proxy warfare is often not the quickest or easiest way to be responsive because relationships with surrogate actors require substantial time to establish and to see any benefits on the ground.

If states have other low-cost options besides proxy warfare, why do states choose this path over non-military options?

Proxy Warfare as a Second-to-Last Resort

Not being explicit about the full set of options available to states obscures an alternative explanation for why states choose proxy warfare — one that is unexamined in Groh’s book. Namely, that states may choose to pursue a proxy strategy because it is the next, easiest step after coercive, often non-military, efforts have proved ineffective.

We can think of proxy war as a rung on an escalation ladder that includes diplomatic engagement, intervention in the domestic political system (e.g., support for political parties or politicians), economic sanctions, military threats, proxy warfare, and finally, the direct use of force. As Herman Kahn argues,60 there are many pathways to arrive at any particular rung, but one is that a state turns to proxy warfare when other, less escalatory options have already been tried, and have failed to achieve the intended goals. Research explaining other types of foreign policy choices uses a similar logic: States learn and adapt their policy options and choices based on what has been attempted, and what has been perceived as effective or ineffective, in the past.61

In other words, proxy warfare may sometimes be the “least bad option,” but it may just as often be the second-to-last resort. This is not to say that Groh’s argument — consistent with that of Idean Salehyan and others62 — does not explain some cases. However, close scrutiny of the historical record demonstrates that this explanation is far from being as universal as Groh posits it is. Indeed, much of Groh’s own evidence actually supports the alternative explanation that proxy warfare was the second-to-last resort as opposed to the least bad option.

In Laos, the United States settled on supporting the Hmong militia after first exhausting a number of other options, including economic aid, diplomatic maneuvers to install a favorable government, and military assistance to the Laotian military.63 Similarly, the Reagan administration decided to arm and train the Contras in Nicaragua only after U.S. attempts to court the Sandinista government through diplomatic overtures and aid, as well as efforts to provide covert assistance to political opposition parties, failed.64 In another case Groh touches on, before providing military support directly to the mujahideen in Afghanistan in the 1980s, the United States considered a number of political and economic efforts to counter Soviet actions there, including: suspending arms-control negotiations with the Soviets; encouraging Pakistan, China, and other states to provide arms to Afghan armed groups; and coordinating propaganda campaigns encouraging criticism of the Soviet invasion and bolstering the image of the mujahideen.65

In the South Africa example, Groh downplays the fact that the decision by the South African government to ramp up assistance to Angolan groups happened at around the same time as a decision to covertly deploy thousands of South African ground forces to contribute to the battle.66 Contrary to his expectation that states choose proxy war when they see direct deployments as costly or impossible, South Africa did both. An alternative hypothesis to explain this case is that South Africa turned to the next, cheapest available option — supporting proxies — and quickly supplemented it with the next one, a small-scale, covert deployment. The evidence Groh provides does not clarify which of the two hypotheses were really at work.

Discussing whether to view state decision-making on an escalation ladder, or as an either/or between the limited options of non-intervention or direct military intervention, is not just a thought exercise — it has real-world implications. If proxy war is indeed sometimes a strategy of second-to-last resort, then policymakers will need to look for different indicators when trying to predict future state behavior than those that flow from Groh’s argument. For example, in some cases, the likelihood of states turning to proxy warfare may increase if states have exhausted other, non-military means. Other times, states may turn to proxy warfare even when direct intervention is not very costly. They may simply view proxy warfare as another tool in the toolkit — and perhaps the cheapest option that has not been proven ineffective already.

Tradeoffs of Proxy Warfare

Once a state has decided to pursue a proxy policy, how and when would that policy prove successful? The book dedicates the bulk of its conceptual and empirical work to answering this vital question. Groh is one of only a handful of scholars who have attempted to do so,67 and it serves as his most impressive contribution.

For Groh, successfully supporting a proxy would involve maximizing utility — or the proxy’s short-term ability to “perform the tasks necessary to carry out the intervention” — and efficacy — the proxy’s long-term ability to achieve the state’s objectives.68 Groh argues that how useful and efficacious a proxy can be depends on the coherence of the intervening state’s policy and how well the state can control the proxy.69 For a proxy policy to be coherent, a state must bring the policy in line with its desired objectives, by “tailor[ing] the policy specifically to account for local (target state), global, and domestic conditions.”70 Groh argues that a state is best able to control its proxy when three conditions are met: the state’s and the proxy’s objectives are compatible, the proxy is very capable, and the proxy is dependent on the state’s support.71 This argument brings together insights from academic research on managing interstate alliances with theories of organizational, principal-agent dynamics.

Building on Groh’s work on proxy control and my own research on a similar subject, I identify a few key tradeoffs for states engaging in this form of warfare and some ideas for future research that flow from them. One of the most interesting tradeoffs implicit in Groh’s book is between maintaining covertness and achieving strategic aims. In many of his case studies, he shows that a state’s commitment to concealing its support to a proxy can often undermine other, intermediate goals, such as building the capacity of the proxy or directing its behavior.72 The imperative of secrecy, he argues, limits the type and amount of support a state can provide to its proxy.

His analysis stops short, however, of outlining which types of support are covert-friendly and which are not. For example, to what degree would the presence of advisers on the ground cross this secrecy threshold? On the one hand, Groh argues that India would not send advisers to monitor the Liberation Tigers of Tamil Eelam in Sri Lanka due to concerns that its support would be discovered, but on the other hand, Groh points out that South Africa — which was similarly concerned with secrecy — did send advisers to Angola.73 Future research can do more to uncover exactly what types of support maintain the necessary threshold of covertness that proxy supporters seek.

Another tradeoff is between the goals of a proxy policy and the ability of a state to control the group. In a major contribution to the field, Groh sketches out four distinct types of proxy wars, differentiated by the state’s desired outcome and the stakes involved. In this framework, a state is either (1) “in it to win it”; (2) seeking a “holding action” to maintain the status quo; (3) “meddling” to cheaply alter the status quo; or (4) attempting to “feed the chaos.”74 For a given state, a proxy policy is only effective based on the goal it is pursuing – one of these four goals, according to Groh. In his otherwise helpful discussion of this typology, Groh does not consider the prospect that a state’s goals might conflict with those of its intended proxy. For example, although Groh’s “holding action” involves preserving the status quo, rebellions, almost by definition, desire to shift the status quo through violence. What local rebel would be satisfied with mere “holding actions”? The Hmong in Laos certainly were not, as Groh himself acknowledges.75 Future research should probe how the purposes for which a state uses a proxy can affect both the likelihood that a proxy accepts a partnership with the state to begin with and the prospects that any given proxy will stay on the same page with the state supporter if it does accept.

The final major tradeoff suggested by Groh’s work is a devastating one to the patron: that under some conditions, empowering the proxy to gain the military or political capability necessary to achieve the state’s aims will undermine the state’s ability to manage the proxy in the future. Groh argues that a proxy emboldened by newfound battlefield successes may become more ambitious, leading it to “overreach.”76 Increasing a proxy’s military capability therefore risks creating daylight between the objectives of a state and its proxy, which had previously been in line.

The dangers of increasing a proxy’s capability over time do not stop at the expansion of a proxy’s ambition. It can also reduce the proxy’s dependence on the state sponsor, undermining one of the three variables that Groh argues makes a proxy more beholden to state interests. According to Groh, a proxy’s capability encompasses both military and political capabilities, including a proxy’s ability to gain support from the population.77 But in his case studies, Groh sometimes claims that this popular support undermines dependence on the state intervener, and sometimes he does not. In the case of Sri Lanka, Groh laments that India was not able to sufficiently isolate the Tamil Tigers from alternative sources of support from co-ethnic communities within India. He assesses that this reduced the group’s dependence on India and ultimately empowered it to defy its patron. In Angola, however, Groh notes that South Africa actually helped the National Union for the Total Independence of Angola (UNITA) nurture local support for the movement.78 Despite this support, Groh argues that the group remained highly dependent on South Africa. Wouldn’t South Africa’s efforts to bolster local support be a liability for South Africa, given that such support provided the group with access to alternate sources of funding (e.g., taxation and blood diamonds), thereby reducing its dependence on South Africa?79 Groh does not explain how he arrived at the contradictory conclusions that popular support led to more dependence in the one case, but not in the other. How support from a population affects dependence on an external state remains an unanswered question.

All these tradeoffs reveal a central weakness of Groh’s argument: the three variables that Groh argues produce a favorable proxy relationship — compatibility of objectives, the proxy’s capability, and the proxy’s dependence — are often dependent on one another. A growth in the proxy’s capability affects the compatibility of objectives and the degree of proxy dependence, while the state’s objectives affect how much capability the state helps the proxy to build.

How often can a state strike the right balance? Groh admits this task is difficult and offers some policy prescriptions for how states can manage suboptimal partnerships with proxies, such as through cultivating dependence and using incentives. But he stops short of demonstrating whether these tactics work.

With its numerous conceptual formulations, arguments, frameworks, and prescriptions, Groh’s book often reads like a dizzying handbook for policymakers, complete with a catalogue of 11 (mostly brief) case studies, that would add to the historical breadth of anyone interested in proxy warfare. Although Groh’s book could have done more to address how states arrive at the decision to use this particular tool among a wide variety of options, including non-military ones, its case studies starkly illustrate the tradeoffs inherent in the conduct of proxy warfare. A growing research agenda — of which Groh’s book is a part — is essential to understanding the myriad balancing acts inherent in proxy warfare and reminding policymakers not to view proxies through rose-colored glasses.


Sara Plana is a PhD candidate in the Department of Political Science at MIT, whose dissertation focuses on proxy warfare. Her research touches on the organizational behavior of armed groups, civil-military relations, military effectiveness, civil war, and use of force. 


Image: U.S. Marine Corps.


1 “Timeline: Houthis’ Drone and Missile Attacks on Saudi Targets,” Al Jazeera, Sept. 14, 2019,

2 Olivia Giles, “How Did the Syrian Civil War Become a Proxy War?” National Interest, Sept. 13, 2019,

3 Tyrone L. Groh, Proxy War: The Least Bad Option (Redwood City, CA: Stanford University Press, 2019).

4 Kenneth N. Waltz, Theory of International Politics (Reading, MA: Addison-Wesley, 1979).

5 David Lake, The Statebuilder’s Dilemma: On the Limits of Foreign Intervention (Ithaca, NY: Cornell University Press, 2016).

6 See, Kathleen H. Hicks et al., “By Other Means Part I: Campaigning in the Gray Zone,” (Center for Strategic and International Studies, Washington, DC, July 2019),; and Kathleen H. Hicks et al., “By Other Means Part II: U.S. Priorities in the Gray Zone,” (Center for Strategic and International Studies, Washington, DC, August 2019),

7 Yaroslav Trofimov, “Under Siege, Iran Now Likely To Seek the Upper Hand,” Wall Street Journal, Jan. 3, 2020,; “Illuminating the South China Seas Dark Fishing Fleets,” Asia Maritime Transparency Initiative, Jan. 10, 2019,

8 “UN Resolution Condemns Russia’s Occupation of Crimea,” Al Jazeera, Dec. 10, 2019,

9 “Advanced Policy Questions for Owen West, Nominee for Assistant Secretary of Defense for Special Operations and Low Intensity Conflict,” U.S. Senate Armed Services Committee, July 12, 2017,

10 Tyrone Groh, Proxy War: The Least Bad Option (Stanford, CA: Stanford University Press, 2019), 29.

11 Russell Goldman, “Kurds, Turkey, and the U.S.: 5 Years of Tension, Alliances, and Conflict,” New York Times, Oct. 16, 2019,

12 Hijab Shah, Melissa Dalton, and Erol Yayboke, Assessment, Monitoring, and Evaluation in Action for Security Sector Assistance (Center for Strategic and International Studies, Washington, DC, 2019),

13 Andrew Mumford, Proxy Warfare (Cambridge, UK: Polity Press, 2013), 12.

14 Andrew Mumford, “Proxy Warfare and the Future of Conflict,” The RUSI Journal 158, no. 2 (2007): 40–46,; Geraint Hughes, My Enemy’s Enemy (Portland, OR: Sussex Academic Press, 2012), 14–15; Seyom Brown, “Purposes and Pitfalls of War by Proxy: A Systemic Analysis,” Small Wars & Insurgencies 27, no. 2 (2016): 243–57,; Tyrone L. Groh, Proxy War: The Least Bad Option (Stanford, CA: Stanford University Press, 2019), 10–11, 51–52.

15 Brown, “Purposes and Pitfalls of War by Proxy: A Systemic Analysis,” 255. See also, Robert Malley, “Why the Middle East Is More Combustible than Ever,” Foreign Affairs 98, no. 6 (November/December 2019),

16 Malley, “Why the Middle East Is More Combustible than Ever.”

17 Malley, “Why the Middle East Is More Combustible than Ever"; Geraint Hughes and Christian Tripodi, “Anatomy of a Surrogate: Historical Precedents and Implications for Contemporary Counter-Insurgency and Counter-Terrorism,” Small Wars & Insurgencies 20, no. 1 (2009): 23,

18 Erica Gaston and Douglas Ollivant, “US-Iran Proxy Competition in Iraq,” New America, Feb. 10, 2020), 17–21,; Erica Gaston and András Derzsi-Horváth, “Iraq After ISIL: Sub-State Actors, Local Forces, and the Micro-Politics of Control,” Global Public Policy institute, April 6, 2018,; Kim R. Cragin, “Semi-Proxy Wars and U.S. Counterterrorism Strategy,” Studies in Conflict and Terrorism 38, no. 5 (2015),; Malley, “Why the Middle East Is More Combustible than Ever”; Thanassis Cambanis et al., Hybrid Actors: Armed Groups and State Fragmentation in the Middle East (New York: Century Foundation, 2019).

19 See, e.g., Yaacov Bar-Siman-Tov, “The Strategy of War by Proxy,” Cooperation and Conflict, no. 19 (1984): 263–65; Karl W. Deutsch, “External Involvement in Internal War,” in Internal War, ed. Harry Eckstein (New York: Free Press of Glencoe, 1964), 102.

20 See, e.g., Mumford, Proxy Warfare, 1–2, 11; Daniel Byman, Deadly Connections (Cambridge, UK: Cambridge University Press, 2007); Daniel Byman, “Why Be a Pawn to a State? Proxy Wars From a Proxy’s Perspective,” Lawfare, May 22, 2018,; Idean Salehyan, “The Delegation of War to Rebel Organizations,” Journal of Conflict Resolution 54, no. 3 (2010): 493–515,; Jeffrey M. Bale, “Terrorists as State: Separating Fact from Fiction,” in Making Sense of Proxy Wars : States, Surrogates & the Use of Force, ed. Michael A. Innes (Washington, D.C.: Potomac Books, 2012), 1–30; Cragin, “Semi-Proxy Wars and U.S. Counterterrorism Strategy.”

21 For different criteria and discussions of proxies or of proxy war, see, e.g., Mumford, Proxy Warfare, 1–16; Candace Rondeaux and David Sterman, “Twenty-First Century Proxy Warfare: Confronting Strategic Innovation in a Multipolar World,” New America, Feb. 20, 2019, 10–11,; Bale, “Terrorists as State: Separating Fact from Fiction,” 27–29; Hughes, My Enemy’s Enemy, 1–14; Groh, Proxy War, 28–29; Thomas Waldman, “Vicarious Warfare: The Counterproductive Consequences of Modern American Military Practice,” Contemporary Security Policy 39, no. 2 (2018): 181–205,; Chris Loveman, “Assessing the Phenomenon of Proxy Intervention,” Conflict, Security & Development 2, no. 3 (December 2002): 32–33,; Amos C. Fox, “Conflict and the Need for a Theory of Proxy Warfare,” Journal of Strategic Security 12, no. 1 (2019): 44–71,

22 Douglas Ollivant and Erica Gaston, “The Problem with the Narrative of ‘Proxy War’ in Iraq,” War on the Rocks, May 31, 2019,; Vincent Durac, “Yemen’s Houthis – and Why They’re Not Simply a Proxy of Iran,” The Conversation, Sept. 19, 2019,; Adam Taylor, “Who Are the Houthis and How Closely Linked Are They to Iran?” Washington Post, Sept. 16, 2019,; “Iraq: Evading the Gathering Storm,” International Crisis Group, Aug. 29,  2019,; Ranj Alaaldin, “How US-Iran Tensions Could Disrupt Iraq’s Fragile Peace,” Brookings Institution Blog, May 23, 2019,

23 For descriptions of some of these attacks, see, Peter Baker, Eric Schmitt, and Michael Crowley, “An Abrupt Move That Stunned Aides: Inside Trump’s Aborted Attack on Iran,” New York Times, Sept. 21, 2019,; Ben Hubbard, Palko Karasz, and Stanley Reed, “Two Major Saudi Oil Installations Hit by Drone Strike, and U.S. Blames Iran,” New York Times, Sept. 14, 2019,; Helene Cooper and Edward Wong, “Skeptical U.S. Allies Resist Trump’s New Claims of Threats From Iran,” New York Times, May 14, 2019,; Gordon Lubold and Michael R. Gordon, “U.S. Deployment Triggered by Intelligence Warning of Iranian Attack Plans,” Wall Street Journal, May 6, 2019,; Farnaz Fassihi and David D. Kirkpatrick, “Iranian Force Exults in Downing of U.S. Drone With a Feast and a Prayer,” New York Times, June 22, 2019, Ahmed Aboulenein, “U.S. Civilian Contractor Killed in Iraq Base Rocket Attack: Officials,” Reuters, Dec. 27, 2019,

24 Ollivant and Gaston, “The Problem with the Narrative of ‘Proxy War’ in Iraq”; Durac, “Yemen’s Houthis – and Why They’re Not Simply a Proxy of Iran”; Adam Baron, “Foreign and Domestic Influences in the War on Yemen,” Proxy Wars Project, 2019,

25 Groh, Proxy War, 83.

26 Groh, Proxy War, 8.

27 Groh, Proxy War, 11.

28 Groh focuses on internal coherence as well as coherence in relation to the situation in the target state, calibration of international support or adversarial reactions, and with the behavior and interests of the proxy.

29 Malley, “Why the Middle East Is More Combustible than Ever”; Brown, “Purposes and Pitfalls of War by Proxy: A Systemic Analysis,” 246.

30 Groh, Proxy War, 51–52.

31 Brown, “Purposes and Pitfalls of War by Proxy,” 244–45.

32 Brown, “Purposes and Pitfalls of War by Proxy,” 246.

33 Malley, “Why the Middle East Is More Combustible than Ever.”

34 Malley, “Why the Middle East Is More Combustible than Ever.”

35 See, e.g., Renad Mansour and Erwin van Veen, “Iraq’s Competing Security Forces After the Battle for Mosul,” War on the Rocks, Aug. 25, 2017,; Shane Reeves, “What Happens When States No Longer Govern?,” Lawfare, Feb. 13, 2017,; Renad Mansour and Peter Salisbury, “Between Order and Chaos: A New Approach to Stalled State Transformations in Iraq and Yemen” Chatham House, September 2019,

36 Cragin, “Semi-Proxy Wars and U.S. Counterterrorism Strategy”; “Winning the Post-ISIS Battle for Iraq in Sinjar,” International Crisis Group, Feb. 20, 2018, 4–6,; Bilal Wahab, “Iran’s Warming Relations with the PKK Could Destabilize the KRG,” The Washington Institute for Near East Policy, Feb. 6, 2017,; Malley, “Why the Middle East Is More Combustible than Ever.”

37 Gaston and Ollivant, “US-Iran Proxy Competition in Iraq.” Erica Gaston, “Local Forces, Local Control,” Project on Local, Hybrid and Substate Actors in Iraq, Global Public Policy Institute, April 20, 2018,

38 Cragin, “Semi-Proxy Wars and U.S. Counterterrorism Strategy.” Cragin notes that similar dynamics have emerged in Iraq, Yemen, and Lebanon.

39 Examples of these challenges for state patrons can be found in, Geraint Alan Hughes, “Syria and the Perils of Proxy Warfare,” Small Wars & Insurgencies 25, no. 3 (2014): 522–38,; Daniel Byman, “Why Engage in Proxy War? A State’s Perspective,” Lawfare, May 21, 2018,

40 For similar descriptions of overlapping and layered relationships, see also, Malley, “Why the Middle East Is More Combustible than Ever.”

41 See, e.g., Byman, “Why Engage in Proxy War?”; Daniel J. Byman, “Friends like These: Counterinsurgency and the War on Terrorism,” International Security 31, no. 2 (2006): 89,; Eli Berman and David A. Lake, Proxy Wars : Suppressing Violence through Local Agents (Ithaca, NY: Cornell University Press, 2019), 3–4; Stephen Biddle, Julia Macdonald, and Ryan Baker, “Small Footprint, Small Payoff: The Military Effectiveness of Security Force Assistance,” Journal of Strategic Studies 41, no. 1–2 (February 23, 2018): 95–99,; Salehyan, “The Delegation of War to Rebel Organizations,” 505–06.

42 Biddle, Macdonald, and Baker, “Small Footprint, Small Payoff,” 103; Idean Salehyan, “The Delegation of War to Rebel Organizations,” Journal of Conflict Resolution 54, no. 3 (2010): 509,

43 Groh’s contention that he is focusing on nonstate actors because other authors have neglected them in discussions of proxy warfare feels unfair. For a sample of this literature, see, e.g., Mumford, Proxy Warfare, 1–2, 11; Byman, Deadly Connections; Byman, “Why Be a Pawn to a State?”; Salehyan, “The Delegation of War to Rebel Organizations”; Bale, “Terrorists as State: Separating Fact from Fiction”; Cragin, “Semi-Proxy Wars and U.S. Counterterrorism Strategy.”

44 For other discussions of principal-agent theory in proxy warfare, see, e.g., Berman and Lake, Proxy Wars; Salehyan, “The Delegation of War to Rebel Organizations”; Idean Salehyan, David Siroky, and Reed M Wood, “External Rebel Sponsorship and Civilian Abuse: A Principal-Agent Analysis of Wartime Atrocities,” International Organization 68, no. 3 (Summer 2014): 633–61,; Biddle, Macdonald, and Baker, “Small Footprint, Small Payoff,” 100–103.

45 Although a full discussion is beyond the scope of this book review, it is worth noting that the focus on pre-21st-century case studies would also affect the analysis of how to manage domestic and internal coherence in a proxy warfare policy. Any U.S. policymaker considering how to manage proxies today will be significantly more mindful of the post-2001 architecture of counter-terrorism assistance that has emerged, from the interplay and shift in authorities for covert operations, where many of these relationships take place, to institutional developments surrounding “by, with, and through” strategies.

46 Groh, Proxy War, 78. Groh also discusses the proxy dimensions of Saudi intervention in Yemen in a mini case study, but for space reasons, this is not discussed in this book review. See, Groh, Proxy War, 74–75.

47 The Houthis have been a long-standing constituency of Yemeni domestic politics. They ruled Yemen for nearly 1000 years, and prior to the takeover of Sana’a in late 2014, waged no less than 6 major wars against the central government. They also were pitted against other Saudi-backed constituencies in Yemen, and thus had long-standing hostility with and some cross-border engagement with Saudi Arabia prior to the current conflict. For more, see, “The Huthis: From Saada to Sanaa,” International Crisis Group, June 10, 2014,; Peter Salisbury, “Yemen and the Saudi-Iranian ‘Cold War,’” Chatham House, Feb. 18, 2015,; Philip Barrett Holzapfel, “Yemen’s Transition Process: Between Fragmentation and Transformation,” United States Institute of Peace, February 2014, 10–11,

48 Groh’s conclusion is somewhat vague. He notes that the “question that remains is whether Iran controls… the Houthi-Saleh coalition or is just donating assistance.” However, he seemingly answers this by the subsequent page and a half analysis and conclusion that Iran is “meddling,” one of Groh’s four categories of proxy warfare (note: not donated assistance). In a chart placing post-9/11 interventions on a spectrum of donated assistance versus proxy intervention, the “Iran/Yemen” case is also clearly denoted as a proxy intervention. Groh, Proxy War, 78–79.

49 Groh, Proxy War, 28–29.

50 Groh, Proxy War, 28–29, 62.

51 Ollivant and Gaston, “The Problem with the Narrative of ‘Proxy War’ in Iraq.” This categorization of U.S. assistance is based on the starting definitions Groh offers for “donated assistance.”

52 Qassim Abdul-Zahra and Bassem Mroue, “Once Again, Iraq Caught up in Tensions between US and Iran,” Associated Press, May 18, 2019,; Jane Arraf, “Trump Wants To Use Iraqi Base To Watch Iran. Now Iraqi Parties Want U.S. Forces Out,” National Public Radio, Feb. 15, 2019, Tamer El-Ghobashy, “U.S. and Iran Compete to Shape New Iraqi Government but Fall Short,” Washington Post, Sept. 25, 2018,; Edward Wong and Eric Schmitt, “U.S. Pressures Iraq Over Embrace of Militias Linked to Iran,” New York Times, March 19, 2019,

53 Even some of the leading Shi’a PMF groups closely affiliated with Iran may not meet definitions of a true proxy, given that many groups demonstrate substantial autonomy and agency, or that Iran does not appear to have full control and direction of all (even most) of their actions. Gaston and Ollivant, “US-Iran Proxy Competition in Iraq.”

54 Gaston and Ollivant, “US-Iran Proxy Competition in Iraq”; Ollivant and Gaston, “The Problem with the Narrative of ‘Proxy War’ in Iraq.”

55 Joshua Shifrinson, “The ‘New Cold War’ with China Is Way Overblown. Here’s Why,” Washington Post, Feb. 8, 2019,; Oystein Tunsjo, The Return of Bipolarity in World Politics: China, the United States, and Geostructural Realism (New York: Columbia University Press, 2018); Brooks and Wohlforth, “The Rise and Fall of the Great Powers in the Twenty-First Century” International Security 40, no. 3 (Winter 2015/16): 7–53,; Editorial Board, “The U.S. and China Are on the Brink of Cold War 2.0. This Is How to Avoid It,” Washington Post, Nov. 29, 2018,; Robert D. Kaplan, “A New Cold War Has Begun,” Foreign Policy, Jan. 7, 2019,; Michael E. O'Hanlon and Sean Zeigler, “No, We Aren’t on the Brink of a New Cold War with Russia and China,” USA Today, July 12, 2019, ; Odd Arne Westad, “The Sources of Chinese Conduct: Are Washington and Beijing Fighting a New Cold War?” Foreign Affairs 98, no. 5 (September/October 2019),; Susan A. Thornton, “Prospects for Co-Evolution in Sino-American Relations," National Committee on U.S.-China Relations, Barnett-Oksenberg Lecture on Sino-American Relations, Shanghai, May 15, 2019,

56 Tyrone L. Groh, Proxy War: The Least Bad Option (Stanford, CA: Stanford University Press, 2019), 37.

57 See, for instance: Groh, Proxy War, 43; Idean Salehyan, “The Delegation of War to Rebel Organizations,” Journal of Conflict Resolution 54, no. 3 (June 2010): 493–515,; Idean Salehyan, Kristian Skrede Gleditsch, and David E. Cunningham, “Explaining External Support for Insurgent Groups,” Internationl Organization 65, no. 4 (Fall 2011): 709–44,; Daniel Byman and Sarah E. Kreps, “Agents of Destruction? Applying Principal-Agent Analysis to State-Sponsored Terrorism,” International Studies Perspectives 11, no. 1 (February 2010): 1–18,; Jeremy M. Berkowitz, “Delegating Terror: Principal–Agent Based Decision Making in State Sponsorship of Terrorism,” International Interactions 44, no. 4 (2018): 709–48,; Zeev Maoz and Belgin San-Akca, “Rivalry and State Support of Non-State Armed Groups (NAGs), 1946–2001,” Internatonal Studies Quarterly 56, no. 4 (December 2012): 720–34,

58 Groh, Proxy War, 91.

59 Groh, Proxy War, 91.

60 Herman Kahn, On Escalation: Metaphors and Scenarios (Westport, CT: Praeger, 1965), chap. 2.

61 For example, Downes argues that democracies turn to civilian victimization as a “tactic of later resort” after other strategies in a war have turned out to be ineffective. In their investigation of how states construct their perceptions of success and failure in war, Johnson and Tierney aptly show that “perceptions of success [and failure]... shape current foreign policy options and decisions.” Alexander B. Downes, Targeting Civilians in War (Ithaca, NY: Cornell University Press, 2008), 33. Dominic Johnson and Dominic Tierney, Failing to Win: Perceptions of Victory and Defeat in International Politics (Cambridge, MA: Harvard University Press, 2006), 14.

62 Salehyan, “The Delegation of War to Rebel Organizations”; Salehyan, Gleditsch, and Cunningham, “Explaining External Support for Insurgent Groups”; Andrew Mumford, “Proxy Warfare and the Future of Conflict,” The RUSI Journal 158, no. 2 (2013): 45,; Andrew Mumford, Proxy Warfare (Cambridge, UK: Polity Press, 2013); Daniel Byman, Deadly Connections: States that Sponsor Terrorism (New York: Cambridge University Press, 2005).

63 Groh, Proxy War, 131.

64 Groh, Proxy War, 58–59. “Memorandum of Notification Prepared in the Central Intelligence Agency for the Special Coordination Committee,” Dec. 5, 1980, Foreign Relations of the United States 1977–1980, Vol. XV, Central America, 1977–1980, Office of the Historian, Although the policy toward Nicaragua officially changed once Ronald Reagan became president, by winter 1980–81, the Carter administration had already begun to acknowledge that the non-military policy toward the Sandinista government was not having the intended effect, and had accordingly suspended that aid. Indeed, in a series of State Department and National Security Council memos, U.S. officials gravely noted evidence that the Nicaraguan government was aiding Salvadoran rebels. “496. Memorandum From Robert Pastor of the National Security Council Staff to the President’s Assistant for National Security Affairs (Brzezinski),” Jan. 16, 1981, Foreign Relations of the United States 1977–1980, Vol. XV, Central America, 1977–1980, Office of the Historian,; “326. Memorandum From the President’s Assistant for National Security Affairs (Brzezinski) to President Carter,” Jan. 2, 1981, Foreign Relations of the United States 1977–1980, Vol. XV, Central America, 1977–1980, Office of the Historian,

65 “Document 8. Memorandum for The President from Zbigniew Brzezinski, ‘Reflections on Soviet Intervention in Afghanistan,’ December 26, 1979,” Dec. 26, 1979, The National Security Archive,; “Memorandum, ‘Our Response to Soviet Intervention in Afghanistan,’ Brzezinski to the President, December 29, 1979,” Dec. 29, 1979, National Security Archive,; “Memorandum, ‘Results of the NSC Meeting, January 2, 1980,’ Brzezinski to the Vice President, the Secretary of State and the Secretary of Defense, January 2, 1980,” Jan. 2, 1980, National Security Archive,

66 Groh, Proxy War, 161.

67 Erica Borghard, “Friends with Benefits? Power and Influence in Proxy Warfare," Columbia University Dissertation; Byman and Kreps, “Agents of Destruction?”

68 Groh, Proxy War, 83.

69 Groh, Proxy War, 11.

70 Groh, Proxy War, 11.

71 Groh, Proxy War, chap. 4.

72 Groh, Proxy War, 153, 171, 198.

73 Groh, Proxy War, 171, 198.

74 Groh, Proxy War, 8–9.

75 Groh, Proxy War, 152.

76 Groh, Proxy War, 14, 102.

77 Groh, Proxy War, 100, 175. Here, Groh draws from some counterinsurgency research that indicates population support is critical to an insurgency’s survival.

78 Groh, Proxy War, 170.

79 “Final Report of the UN Panel of Experts on Violations of Security Council Sanctions against UNITA, the ‘Fowler Report’, S/2000/203,” March 10, 2000, United Nations Security Council Committee,