Rethinking Proxy Warfare

Great power competition is on the rise, and rivalries among regional powers in the Greater Middle East and its periphery are intensifying. In this new era of proxy warfare, the diffusion of technology, information, and weapons has loosened the state’s monopoly on the use of force. This is occurring against a backdrop of a faltering Euro-Atlantic alliance and deadlock in the United Nations Security Council that has undercut attempts to mitigate the adverse effects of conflict in the region. The use of third-party armed forces that lie outside the constitutional order of states directly or indirectly engaged in hostilities in Syria, Iraq, Yemen, Libya, Afghanistan, and Ukraine, in particular, has upended established international norms in the realm of international law and raised serious questions about the efficacy of current U.S. policies.

As successive White House administrations have shown in grappling with decisions ranging from whether to support Libyan militias in their fight against ISIS, to a possible withdrawal of support to rebel forces in northern Syria, or assistance in the Saudi air campaign in Yemen, there are few easy solutions. Little has been written about the changes wrought by strategic innovations in proxy force deployment and the use of weapons, communications, and information—all of which have transformed the nature of strategic surprise, made proxy forces more numerous, and in some case made proxies more lethal. The potential peril of these strategic choices is exceedingly high, but all too often policy claims about proxy warfare are made with limited data and insight about what is actually occurring on the ground.

Proxy wars often escalate into brutal conflicts that spill across borders. Rival sponsors commonly employ strategies that support the use of ever more questionable and lethal tactics by their own proxies. In each instance, murky sponsor motivations and covert proxy connections raise barriers to attributing actions to actors. Intelligence sharing, air campaigns, battlefield detentions, joint strikes, and targeted kill/capture operations supported by principals and executed by agents blur lines of command responsibility. Reliance on proxies has simultaneously precipitated and reinforced a feedback loop of ever more expansive state secrecy, predatory corruption, and lack of transparency in the realm of global finance, arms, and energy trading.

As a result, when drones strike, ballistic missiles cross boundaries, chemical weapons explode, and bots attack, “command and control” takes on a whole new meaning. The tangle of relationships between irregular proxy forces and their sponsors often obscures how orders are issued and who sets the rules of engagement. When a proxy combatant operating outside the constitutional order of a state involved in conflict provides targeting coordinates for air strikes, supplies intelligence that leads to chemical weapons attacks, or mobilizes bots to amplify disinformation campaigns, “red lines” are often crossed without consequence. Under these circumstances, the potential for misattribution, escalation, and blowback raises the stakes for sponsors considerably. With the five permanent members of the UN Security Council frequently deadlocked in a 3–2 split when something goes wrong on the battlefield, the procedures for redress are uncertain and sanctions increasingly unenforceable. All these factors add up to a profound change in the global order, one that will test the United States, its allies, and the international community in new ways.

The dominant analysis in Washington focuses on direct and indirect military support to combatants on the premise that such approaches lower costs and risks. Inadequate attention is paid to the strategic innovation states undertake in combining hard and soft power to advance their interests. There appears to be even less critical understanding of how these strategies shape and are shaped by local dynamics and socio-political divides. Confronting Russia’s increasingly aggressive approach to the West; Iran’s strategy of deterrence and efforts to extend its influence in the region; and China’s competitive challenges, will require a sharper understanding of today’s proxy wars and what tomorrow’s conflicts might look like.

Given the complexity of regional conflicts in the Greater Middle East and its periphery, contemporary proxy warfare appears to have the potential to put the world on course for a major collision. At the same time, norm-breaking violence is rending societies in much of the region. Current analysis, however, is largely based on outmoded interpretations of the Cold War, the global war on terror, and counterinsurgency campaigns. Much of the extant research focuses on the experience of the United States, demonstrating the need for more extensive primary and secondary source review in languages other than English on the experience of other states with proxy strategies.

The United States and other world powers now face important questions at the dawn of a new age in the future of conflict: When does norm bending become norm breaking beyond repair? How does, for example, Syria’s reliance on a combination of Russian, Iranian, and pro-regime Syrian forces in air campaign targeting processes impact accountability for civilian casualties and related collateral damage, particularly in an environment where Syria has demonstrated a willingness to use chemical weapons? When Houthi missiles strike inside Saudi Arabia and Hezbollah trainers are on the scene assisting Houthi rebels, is a counterstrike inside Iran a proportionate response? What can be done to ensure that a norm reshaped by proxy forces does not become grounds for escalation to a third world war? Answers to these questions are neither easy nor quick to hand. The scale and pace of global security demands a rethinking of proxy warfare in the twenty-first century.

This study attempts to do just that by examining a significant sample of the existing academic and think tank literature on the topic. It maps many of the main theoretical disputes about proxy warfare. In addition to looking at the Cold War and post-Soviet evolution of proxy strategies, our analysis focuses on conflicts in the regions of concern, state building, international law, and irregular forces.¹ It identifies gaps in the existing literature and highlights current and future emerging threats. Although far from comprehensive, the study attempts to tease out the policy challenges posed by the rise of proxy warfare through a survey of English-language academic, journalistic, and think tank literature.

The study is divided into four main sections, including this one. This section begins with an exploration of a substantial sample of the existing literature and conceptual challenges posed by proxy warfare. It interrogates state-centric models of sponsor-proxy relations and teases out the complex motivations behind proxy strategies. The second section, “Principal Rivalries and Proxy Dilemmas,” provides a brief historical overview of the evolution of proxy warfare from the end of World War II through the Cold War with a focus on the Greater Middle East and its periphery. The third section, “A New Age of Proxy Warfare,” maps out the emergent properties of twenty-first century strategies employed by states and other actors to advance their interests. The concluding section examines the analytical challenges ahead as the United States and its allies confront new dimensions of a strategy that delivers political and economic advantages in the short term but poses long-term challenges to global stability. In addition to these four main sections, the report includes an executive summary and an atlas of proxy warfare in the Greater Middle East and its periphery.

It is important to note that the wide array of states and non-state actors engaged in conflict in these regions makes it impossible to account for every angle. As a result, our inquiry prioritized an examination of the motivations, goals, and strategic objectives of sponsors and their proxies. We focused on major state powers actively engaged in providing support to armed forces active in Syria, Iraq, Yemen, Libya, Afghanistan, and Ukraine including the United States, Russia, Turkey, Iran, Saudi Arabia, and other Gulf States.²

A fundamental first step towards a discussion of the character of proxy warfare today, its future, and the costs and risks of embracing proxy strategies is laying down a conceptual framework. This is tougher than it might seem. Proxy warfare is not a new subject of analysis, but it is an area that has few well-marked boundaries or definitions. The phrase dates at least to the beginning of the Cold War and has risen in use ever since. Moreover, while the term may be of mid-twentieth century origin, the basic idea of engaging in war while someone else does the fighting—by proxy—is likely as old as warfare itself.

Though the concept is old, the current state of proxy warfare analysis is reminiscent of the state of post-9/11 counterinsurgency research in the early stages of the Afghanistan and Iraq conflicts. In those cases, the failure to have clear ideas about counterinsurgency led to years of misguided policy. As with the current literature on proxy warfare, a significant amount of research from prior periods was available, but few synthesized observations were applicable to the policy challenges and particularities of those conflicts.

Uniform definitions of the term “proxy warfare” are hard to come by. This is partly because, as Andrew Mumford notes in his 2013 monograph on the topic, proxy wars have been “chronically under-analyzed” and under-theorized.³ Until very recently, the moral and legal conundrums posed by current proxy wars on international norms and the standing of the United States as a strategic partner have received little serious introspection in Washington’s interagency policy community, as Anthony Pfaff has noted.⁴ The covert nature of most proxy strategies has also limited analysis. Those that are overt tend to be the product of specific dynamics regarding the strength and motive of the supporter of the proxy that allow it to embrace a more public strategy, introducing substantial selection effect biases.⁵

Proxy wars have been “chronically under-analyzed” and under-theorized.

The question of definitions is essential to good policymaking. A lack of clarity as to what is meant by “proxy warfare” and what qualities define a useful proxy strategy for the United States have been on full display since the 9/11 attacks. The prolonged and sometimes heated policy debates in successive White House administrations over sponsorship of paramilitary and militia forces in Syria, Iraq, Libya, and Afghanistan have profoundly impacted U.S. alliances and affected the stability of the Greater Middle East. Tensions between those in the responsibility to protect (R2P) camp who called for interventions in Libya and Syria and those who feared blowback risks and cautioned against widening foreign entanglements high during the Obama administration.⁶ Frictions over whether to arm Kurdish People’s Protection Units (YPG), a U.S.-designated terrorist organization and longtime antagonist of Turkey, a critical NATO ally in the region, called into question the efficacy of backing forces that lie outside and challenge the constitutional order of states in order to contain perceived threats to stability. Despite heated debate, little in the way of formal congressional authorization for use of military force or clear strategic guidance regarding the benefits, risks, and endgame of proxy engagements has emerged out of these debates.

Much of the theorizing around proxy warfare draws on Cold War analysis of the rivalry between the United States, Russia, and China during the conflicts in Cuba, Vietnam, Angola, Afghanistan, El Salvador, and Nicaragua. The analytical focus on the Cold War has many roots, not least of which is the vast investment in strategic thinking on nuclear deterrence as well as Soviet support for revolutionary movements. Another factor is that the collapse of the Soviet Union resulted in the declassification of thousands of official U.S. documents, and for a brief time opened Soviet archives, which for years had been sealed in hermitic secrecy. Newfound sources also prompted the publication of a slew of political histories, journalistic accounts, and personal memoirs, and many Cold War participants and witnesses have also been more willing to be interviewed.⁷

Studies on state-sponsored terrorist and insurgent groups such as Hezbollah in Lebanon and Syria also offer a few theoretical clues. Of particular note for its conceptual clarity are Daniel Byman’s Deadly Connections and his other publications on proxy warfare and state sponsorship of terrorism.⁸ Many significant studies on external support during civil wars and on state sponsorship of terrorism have also touched on the subject, yet both these fields capture only a subset of the broader challenges of proxy warfare. Idean Salehyan, Reed Wood, and David Siroky, among others, have, for instance, made significant contributions to understanding principal-agent relations and ways in which external sponsorship of rebels leads to atrocities.⁹

The literature on state sponsorship of terrorism is predominantly rooted in Cold War conceptions that emphasize the power of highly centralized states and their influence over non-state proxies rather than the agency of groups themselves.¹⁰ Moreover, much of the discussion and analysis of proxy warfare in the American academy and Washington policy circles is highly politicized and fails to critically examine the “good for me but not for thee” orthodoxy of partnered military operations.¹¹

This critique of the focus upon the power of highly centralized states finds echoes in more recent literature on state co-optation of rebel forces and the integration of irregular paramilitary and militia forces into the strategic playbook of many principal sponsors of proxy warfare. As Ariel Ahram notes in his book Proxy Warriors, “few states have ever actually sought a complete monopoly over military force, much less possessed it. States engage continuously in negotiation, collaboration, and domination of external and internal challengers to assert and maintain a hold on power.”¹² In the context of conflicts in the Greater Middle East, Afshon Ostovar suggests in his recently published book Vanguard of the Imam¹³ that the Iranian Revolutionary Guard Corps (IRGC) and the Basij paramilitary units stand out as examples of the type of phenomenon that Ahram describes as an as-yet unresolved “competition and cooperation between state and embedded societal elites for control of coercion” that has for decades marked the post-colonial state-building project in the region.¹⁴

Several international policy analysts and think tanks have, like Ahram, ably tracked the connection between proxy wars and the rise of paramilitaries and militias since 2001.¹⁵ The rise of what András Derzsi-Horváth and Erica Gaston call “local, hybrid and sub-state security forces” in Iraq during recent clashes with ISIS is just one example of how competition between principal rivals is increasingly defining and distorting competition between local elites for control over territory and resources.¹⁶ “Loose command and control” over proxy militias and paramilitaries, Derzsi-Horváth and Gaston note, poses serious problems not only for Iraqi state stability but for the increasingly tenuous relationship between two key NATO allies in the region—the United States and Turkey.¹⁷ Both countries share an interest in containing Iranian-backed Popular Militia Forces (PMF) but Washington’s decision to back Kurdish forces has cast considerable doubt on the resilience of this Turkish-American partnership.¹⁸

Local militias are attractive to sponsors like the United States because they provide a ready source of local expertise in a given terrain.

Similar dynamics have precipitated sharp tensions between the United States and other erstwhile partners in South Asia. In Afghanistan, American backing for a variety of “auxiliary police,” “tribal gendarmerie,” and militias who operate outside established law has been a subject of friction between Washington and Kabul since 2001. As Antonio Giustozzi, Mark Sedra, Michael Bhatia, and other well-known experts on the Afghan conflict have noted, war and politics have long been shaped by the interaction of militias with the state, and local militias are attractive to sponsors like the United States because they provide a ready source of local expertise in a given terrain.¹⁹

Though Afghan militia proxies may seem expedient, they are not always very effective at supporting the project of rebuilding the state. Various think tanks and human rights groups have also traced the outgrowth and impact of U.S.-backed paramilitaries, such as the Afghan Local Police in Afghanistan, where various stripes of Northern Alliance, Hizb-e Islami, and Taliban fighters have been “reintegrated” into a security apparatus with only the loosest of linkages to constitutional order.²⁰

Just over the Afghan border, as Steve Coll and Stephen Tankel document in their books on Pakistan’s Inter-Services Intelligence agency and its relations with the Taliban and Laskar-e-Taiba, Pakistan’s military elite has long viewed its investment in proxies as critical to creating strategic depth in the face of threats from India.²¹

Others have documented the proliferation of militias in Syria, Yemen, Libya, and Ukraine, where principal rivalries between the United States and Russia, as well as Iran and Saudi Arabia, are heating up competition between local elites for support of their own proxy forces. But there are few book-length studies that examine and compare in detail the nature and character of proxy wars that are now raging across the Middle East, North Africa, and South Asia.

Much of the journalistic and think tank coverage on conflicts in the region relies on interviews with participants and key decision-makers, but leaves open, primary source data virtually untouched. For some countries mired in proxy conflict today—notably Syria, Iraq, and Ukraine—journalists and analysts have begun to exploit digital traces of conflicts by sifting through social media platforms and other online data; the work has been impressive, but it only scratches the surface.²² However, on other conflicts, most notably Yemen and Libya, the use of digital forensics to find fresh analysis is rare, demonstrating both the difficulties of tracking online sources as well as verifying existing digital evidence absent a strong community of locally based correspondents and researchers in those countries.²³

Several recent book-length scholarly publications and articles stand out for their conceptual clarity regarding the subject of proxy warfare. In addition to recent books on the subject by Geraint Hughes, Mumford, and Michael Innes, other important contributions that touch on related topics such as state sponsorship of terrorism and patron-client relationships during counterinsurgency include recent works by Walter Ladwig and Daniel Byman.²⁴ Yet few works in this category adequately address the cross-cutting dynamics that drove the rash of intra-state wars and the rise of transnational social movements following the 1979 Iranian revolution and the collapse of the Soviet Union in 1991. Many studies focus primarily on the outcomes of support upon non-state actors while too often treating the state conflicts that underlie many proxy wars as external factors. Likewise, the predominance of English-language American and European scholarly work on strategic studies also tends to narrow the topic and geographical focus considerably, as has been documented recently by several researchers.²⁵

As Idean Salehyan observed in his 2011 book Rebels Without Borders:

A large share of research on civil conflict treats nation-states as hermetically sealed, independent units. Country-level attributes and processes—such as income inequality, ethnic tensions, dependence on primary commodities, and the responsiveness of political institutions—dominate theories of civil war. This is especially true of works that draw heavily on statistical analyses.²⁶

Salehyan notes in a separate article on related themes that while Iran and Israel have engaged in a deadly proxy war with each other for years, with Iran providing support to groups like Hamas and Hezbollah to target Israel, the widely used Militarized Interstate Dispute database records no dispute between the two countries because the conflict has been engaged in via indirect means.²⁷

Other commentators have noted a tendency to debate causes of conflict like ancient hatreds or the role of Islam in the Middle East while ignoring the impact of proxy wars and the Cold War.²⁸ The U.S. experience of engagement in proxy warfare in the Middle East is covered extensively by these scholars, but the experiences of rival states such as Iran and Russia are scantly covered in existing literature.²⁹ Likewise, critical examinations of the impact of divisive European colonial policies on social structures and political development—and what William Easterly has called the “tyranny” of European and North American experts—has primarily remained the preserve of development studies specialists whose analysis rarely integrates scholarship on the counterinsurgency campaigns that were so pivotal in the colonial and early post-colonial period.³⁰

A large share of research on civil conflict treats nation-states as hermetically sealed, independent units.

All of these analytical approaches offer a window onto the variegated nature of proxy strategies but there is nothing in the way of a unified theory on what drives proxy wars, as Geraint Hughes explains in his book on the subject.³¹ Nor is there much convergence around how to assess a principal sponsor’s support for conventional forces versus irregular forces or how best to measure the strength of a sponsor’s direct or indirect influence over proxies.

Three main threads, nonetheless, emerge from the literature: the central role of the United States, Russia, and China as superpowers in shaping proxy strategies; the clash between capitalism and socialism in the international arena; and the progression from wars for independence after the collapse of the French and British colonial empires after WWII to the proliferation of intra-state conflicts following the collapse of the Soviet Union. These themes are still relevant today, but contemporary academic analysis often fails to capture the experience of the regional client states in the Middle East, North Africa, and South Asia in the post-WWII period.

As can be seen from even the above snapshot of existing literature, the subject has been studied from many angles. There is, however, little accord on who qualifies as a principal or an agent in a proxy relationship, what shapes proxy-sponsor relations, what constitutes command and control, or how best to analyze the problems that arise with proxy strategies. Little has been written on the ways that access to remote targeting capabilities such as drones and ballistic missiles have transformed proxy-sponsor relations in places like Yemen and Syria. Nor is there much consensus on what, if any, distinction can be made between strategies that rely primarily on surrogate irregular forces versus those that rely primarily on the conventional forces of a client or allied state. There are many debates, but most agree that the logic of proxy warfare is firmly rooted in the concept of “limited war.”

In limited war, as Sir Lawrence Freedman has noted, “belligerents choose not to fight at full capacity, in order that a conflict neither gains in intensity nor expands in space.”³² Limited war is characterized by mutual acceptance of external constraints imposed by the prospect of mutual annihilation. Conceptually, limited war is deliberate step back from all-encompassing “total war”—the kind of destructive force that occurred in World War I. Limited war took on a new dimension after the Soviet Union tested its first nuclear weapon in 1949—only four years after the United States dropped nuclear bombs on Hiroshima and Nagasaki. As the Soviet-American arms race heated up, the doctrine of mutually assured destruction became the bedrock of Cold War strategic thinking.³³

It also spawned a non-proliferation regime which for nearly 70 years has sought, with mixed results, to limit the number of states with access to weapons of mass destruction, ballistic missiles, and other high-powered standoff capabilities. Following revelations about Israel’s nuclear weapons program in the 1960s, escalation dominance appeared to become ever more central to the military doctrine of many former Cold War client states in the Greater Middle East and its periphery. In addition to Israel, India and Pakistan also have nuclear weapons. Iran has tried to acquire them. Iraq and Syria have at various points tried to develop their own weapons of mass destruction and ballistic missile capabilities, prompting preemptive strikes by Israel and intervention from other external powers. Saudi Arabia and the UAE are among the world’s leading importers of weapons.³⁴ Virtually all the major regional powers have expanded their ballistic missile programs in part as a response to perceived threats from regional rivals and external adversaries.

Yet even as more states have acquired powerful weaponry in the Greater Middle East and worked to attain parity with rivals, their ability to project power is hamstrung in part by historical dependencies on external powers, a circumstance that has impeded the ability of former Cold War client states to modernize their militaries. The majority of former client states are dependent on external providers such as the United States, Russia, and China for weapons and military equipment. Many draw on close-knit networks of ruling tribes, clans, or families and well-connected powerbrokers to form the backbone of their officer corps. Only a handful rely on conscription to fill their ranks. All these factors contribute to a highly unsteady regional military balance in the Greater Middle East and its periphery that constrains the means by which rival states can use conventional forces to advance their strategic aims.

Yet competition remains, making limited war the next best option and raising the appeal of irregular proxy forces that lie outside the chain of command dictated by a state’s constitutional order. Irregular militias, paramilitaries, and private security contractors not only fill in gaps, because they are not directly beholden to the public, they could operate outside the normative lines conventional militaries are obligated by international law to observe. As long as proxies exact their toll on rivals in a way that is plausibly deniable by their sponsors, the reasoning goes, sponsors can deny command responsibility. Concealing and controlling narratives around command responsibility is critical to containing costs and preventing escalation.³⁵

Competition remains, making limited war the next best option and raising the appeal of irregular proxy forces that lie outside the chain of command.

Paradoxically, the need for secrecy greatly complicates sponsors’ ability to insulate themselves from escalation risks. As seen with Russia’s use of private military security contractors to back separatist forces in Ukraine, the pressure to conceal can greatly complicate the command structures and impose limits on sponsors’ ability to exert control over proxies.³⁶ The downing of MH17, a Malaysian Airlines commercial plane that flew over Ukraine airspace in 2014, is but one example of the potential risks posed by relying on proxies to advance limited war aims. The shootdown, which killed 298 people, among them Dutch, Australian, Indonesian, and British nationals, was ultimately attributed to Russian-affiliated forces and prompted stringent international sanctions against Russia. In a highly globalized and interconnected world, the potential for proxy warfare to expand in geographic scope and increase in lethality is a feature that distinguishes today’s strategic balance from that of the Cold War. Escalation risks have grown in an international system destabilized by the transition from bipolarity at the end of the Cold War to multipolarity en route to the Arab Spring.

The rise of non-state actors, transnational social movements, and the diffusion of remote targeting and high-powered weaponry have been hallmarks of that transition. The shift to multipolarity has introduced many more armed actors into the mix, some of whom are pursuing revolutionary or apocalyptic goals that are heedless of geographic boundaries and that are fundamentally at odds with states’ interests in limited war aims. At the same time, globalization has seen the rapid integration of transportation, communications, and supply chains. Under these circumstances, borders and boundaries are increasingly difficult to defend.

In some cases, fears that weapons of mass destruction might be transferred to proxies can encourage escalation. For example, Israel has reportedly conducted air strikes in Syria in part with the intention of preventing and deterring transfer of chemical weapons and sophisticated missile technology to Hezbollah that might then be used in a war with Israel.³⁷ Proliferation fears can drive escalation even when such fears are not well founded, as seen in the construction of the case for the invasion of Iraq based on arguments regarding weapons of mass destruction and terrorism. All of these factors raise the risk of miscalculation and greatly complicate efforts to tamp down escalation. In an international environment where multipolarity, the proliferation of high-powered weaponry, and armed groups are increasingly shaping threat perceptions, the covert nature of sponsor-proxy ties paradoxically raises the risk of strategic miscalculation.

The question of what constitutes proxy warfare remains a highly contested and under-analyzed issue. There are a number of examinations and efforts to define the subject. These efforts provide insight, yet they suffer from flaws. A legally focused definition that defines proxy warfare as sponsorship of conventional or irregular forces that lie outside the constitutional order of states is best placed to avoid these flaws and form a platform to reassert accountability and clear lines of command responsibility, which is essential to avoiding the threats posed by twenty-first century proxy warfare.

The conceptual roots of proxy warfare have antecedents in Thucydides’ History of the Peloponnesian War. In the classic narrative of the war between Athens and Sparta, expansion and containment are the intertwined strategic impulses that shape the epochal conflict between the two rivals.³⁸ The characteristic strains of conflict described by Thucydides—asymmetric rivalries, rejection of a total war of annihilation in favor of a limited war of attrition, alliance targeting, rhetorical battles over the moral demands of just wars—are all features that are repeatedly described in subsequent historical and analytical narratives of proxy warfare.

Historically speaking, proxy warfare is as old as war itself, but the emergence of international strategic studies as a formal analytical field in the post-World War II era marks a distinctive period in the conceptual genealogy of proxy warfare.³⁹ Notwithstanding debates about the fundamentals of battlefield victories,⁴⁰ there can be little doubt that the dawn of the nuclear age brought with it a new understanding of the meaning and dynamics of “limited war.” Yet, analytical approaches to twenty-first century proxy warfare inevitably run into the thorny problem of definitions.

Even a cursory review of conflict studies literature reveals that there are deep disagreements over what constitutes sponsorship, what defines a proxy, and how state and non-state actors fit into the strategic paradigm. Mumford, for example, defines proxy warfare as the “indirect engagement in a conflict by third parties wishing to influence its strategic outcome.”⁴¹ His definition of proxy war accounts for how states and non-state actors can both be and have proxies.

The dawn of the nuclear age brought with it a new understanding of the meaning and dynamics of “limited war.”

Others have proffered more state-centric views of proxy warfare in which the principal must be a state and the proxy agent a non-state actor. Iran’s sponsorship of Hezbollah, U.S. support for the Contras, and Pakistani support for Lashkar-e-Taiba are often cited as classic examples. Geraint Hughes, for example, adopts a definition of proxy warfare in which only states can be principals and only non-state groups proxies.⁴² Yet this definition separates Hughes’ work from the strategic literature on proxy relationships involving states as agents. At the same time, it excludes the rising phenomena of transnational non-state groups, private military-security providers, and entities with cooperative arrangements with other such groups that appear to deserve analysis as proxy relationships.

Beyond the question of state centrism and the identity of principal and agent, there is substantial debate over what kind of relationship between principals and agents constitutes a proxy relationship. Mumford suggests that “the fulfillment of a strategic goal by proxy does not necessarily have to be a conscious or deliberate act.”⁴³ While this is a useful departure point, Pfaff, for his part, rightly points out that proxy war requires intention—even if the strategy fails or the proxy also seeks goals that are in conflict with its sponsors.⁴⁴ Not simply a definitional nitpick, the disagreement between Pfaff and Mumford reveals the need for better theories on what constitutes proxy warfare and an evidence base to test those theories.

Pfaff describes proxy warfare strategy as “the use of surrogates to replace, rather than augment, benefactor assets or capabilities.”⁴⁵ This definition conceives of a state as a monolithic actor though there is plenty of evidence to suggest that the erosion of state power in the age of globalization has seen non-state actors grow their interests and influence over military affairs. Problematic formulations of the state aside, Pfaff’s conceptualization lines up well with the analysis of Michael Innes and others, in the aptly titled Making Sense of Proxy Warfare. But Innes goes one step further, suggesting that a “symbiosis between state and non-state actors” underpins sponsors-proxy relations and sponsorship takes on many different forms in today’s conflicts in which militias and paramilitaries often serve the interests of multiple actors and private military actors take on state roles, among other phenomena.⁴⁶

The most prevalent formulations of what constitutes proxy war conceptualize proxies as rebel non-state armed forces under formal or informal contract as agents to a principal state as a unitary and often singular actor. But, as some, among them Pfaff, have noted, multipolarity has given way to a “polyarchic” world order⁴⁷ in which the monopoly on the use of force by nation-states is highly atomized and under sway to bureaucracies that tend to do their own thing. Indeed, recent scholarship has emphasized an expanding spectrum of non-state agents from entrepreneurial individuals to networks to classical organizations capable of being part of a proxy strategy, requiring a move beyond analyses that focus solely on organization to organization-cooperative arrangements.⁴⁸

If there is one major point of agreement, however, in the existing literature, it is that proxy warfare is characterized by a distinctive relationship between a principal-sponsor who delegates some authority over the pursuit of strategic war aims to a proxy-agent.⁴⁹ There is also near-universal agreement that the two major risks in proxy strategy center on proxy motivations and modes of fighting and the alignment, or more often, misalignment of principal sponsors’ war aims and those of proxy agents.

Theories that conceptualize proxy warfare as primarily a contest between external state powers miss what has changed. The chaotic reordering of the political order in the Middle East, North Africa, and South Asia that followed closely on the heels of the September 11, 2001 attacks on New York and Washington and intensified with the 2003 U.S. invasion of Iraq and the 2011 Arab Spring has aggravated regional rivalries and stoked sectarian divides. Russia’s recent rebound and China’s rising influence, as well as the intensification of regional rivalries among Gulf States, have in turn compelled the United States to reorient its strategic focus. The high price of direct military confrontation with either Russia or Iran in the Middle East in particular all but ensures that the United States will double down on an off-shore balancing strategy that leverages alliances in these regions.⁵⁰

Proxy warfare is characterized by a distinctive relationship between a principal-sponsor who delegates some authority over the pursuit of strategic war aims to a proxy-agent.

In rethinking proxy warfare, it is important to acknowledge the thin gray line that separates allies and client states.⁵¹ Allies, by definition, agree not only on the nature of the perceived threat but to a shared responsibility to respond to that threat in an all-for-one, one-for-all formulation; even where one state holds an upper hand militarily, implicit in the idea of an alliance is the independence of each party. While client states may share the same perception of a threat and may even agree with their sponsors on a response, it is more often the case that clients are materially dependent on a sponsor and could not otherwise respond or pose a credible counter to a threat on their own.

It also pays to be clear-eyed about the high price of doing business with a stable allied state versus a fragile client state that has just undergone violent regime change. With very few exceptions, when states have deployed proxy warfare strategies in the clientelist model of state to state, military to military support they have historically relied on formal treaties, military technical agreements, or formal diplomatic notes that define relations and terms and lay out the provisional authorities of external actors who serve as advisers or enablers for conventional forces of allied states. In both instances, the rules of engagement are usually explicitly stated and there is little ambiguity in international law about the obligations of combatants even when there may be questions about the legitimacy of certain battlefield tactics or specific events.

However, in weak states with contested constitutional orders that fail to explicitly or comprehensively articulate the relationship between a state’s security forces, its government, and its citizens, it is ultimately the shortcomings of the client state’s conventional national security institutions which often lead sponsors to enter into formal or informal contracts with irregular armed forces. Frequently in these cases, the territorial jurisdiction and legal authorities of externally supported irregular militia or paramilitary forces is murky. Ambiguity can hold a strategic advantage for sponsors and client states, in heightening plausible deniability, but it can also undercut local government legitimacy, not to mention, as Pfaff notes, the credibility of the principal sponsor who may have to answer for a proxy’s excesses.⁵²

As seen in Afghanistan and Iraq from 2001 forward, U.S. efforts to advance its foreign policy objectives “by, with, and through” partners have imposed high economic, political and strategic costs.⁵³ In both Afghanistan and Iraq, the clientelist model of proxy warfare predominated despite the fact that decades of internecine conflict arose directly out of systemic abuses of power by the very same Afghan and Iraqi security institutions that the United States inherited as partners. In the heated aftermath of the 9/11 attacks, however, there was little appetite in the U.S. national security establishment, the UN, and NATO to start from scratch or contravene the orthodoxy of a “light-footprint” approach to intervention and reconstruction.⁵⁴

Successive White House administrations chose instead to work within the constraints of existing local security institutions while stitching together a patchwork of auxiliary irregular forces to fill in capabilities gaps.⁵⁵ This wave of post-Cold War U.S. investment in irregular forces at the same time precipitated parallel support from Pakistan, Iran, and later Russia to rival proxies ostensibly allied with the Taliban in Afghanistan.⁵⁶ In Iraq, meanwhile, Tehran reinforced existing support to Shia militia forces both during its war with Saddam Hussein and later in its not-so-covert competition with Washington.⁵⁷ The United States, for its part, backed an array of paramilitary forces after the 2001 al-Qaeda attacks, most notably the Afghan Local Police and Counterterrorism Pursuit Teams and the “Sons of Iraq” following the 2003 invasion.⁵⁸

The decision to stand up the Sons of Iraq program tapped into the local grievances of tribal leaders in Anbar Province to combat al-Qaeda in Iraq despite concerns regarding the difficulty of later integrating fighters recruited under the program within the Iraq government structure.⁵⁹ Similar logic motivated the U.S. decision to establish the Afghan Local Police (ALP) in 2010. An iteration of the previously disbanded Afghan Auxiliary Police, the ALP was meant to extend the writ of the state by recruiting locally based fighters to challenge the Taliban in remote and contested parts of the country. In theory, ALP fighters would better be able to leverage their expert knowledge of the local terrain and local Taliban to regain control. In practice, the highly centralized nature of the Afghan state, and the Ministry of Interior more specifically, made oversight of ALP forces challenging, while the recruitment of supposed Taliban defectors and locals affiliated with unsanctioned militias in not a few cases raised human rights concerns.⁶⁰

Three important factors are often determinative in shaping a decision to adopt a proxy strategy: the length of supply lines, the limitations of conventional forces, and political constraints that make prolonged military confrontation unattractive to many decision makers.⁶¹ Proxy forces can shorten lines of communication and bring to bear considerable local knowledge of the terrain and stakeholders in a conflict that external sponsors might not otherwise be able to access easily. In addition to flattening the tactical obstacles of range and intelligence, there are significant short-term non-military advantages that both sponsors and proxies derive from their relationship. As one Western military expert suggested the immediate success of battlefield gains at a fraction of the cost of what it would take to mobilize a conventional force produces a “form of military ‘sugar rush’ that can be addictive for policymakers” looking to demonstrate the efficacy of wars fought on the cheap.⁶²

Proxy forces can shorten lines of communication and bring to bear considerable local knowledge of the terrain and stakeholders in a conflict.

This may be especially true in situations where the political tenure of elite decision-makers is shaped by the size of their coalition of support and foreshortened by either a selection cycle or internal and external threats that spur them to demonstrate a decisive ability to effectively wield coercive power.⁶³ In this respect, the U.S. decision to partner with Northern Alliance fighters in Afghanistan in 2001 and the Russian decision to provide backing to ethnic Russian rebel forces in Ukraine in 2014 are notable examples of the “sugar rush” effect, where swift battlefield victories are followed by a hard crash when local politics do not line up with sponsors’ strategic objectives.

The advantage of using irregular forces in each case was in allowing sponsors to project power beyond their own existing capacity, while avoiding the same kind of domestic scrutiny that a direct declaration of hostilities might incur. In each instance, external powers relied on national or subnational forces operating outside of their own direct constitutionally defined chain of command. Yet, there were clear distinctions. In the initial years, U.S. relations with local Afghan forces were governed primarily by a military technical agreement, and later, a status of forces agreement.⁶⁴ In Iraq, U.S. forces initially provided support to Iraqi forces under the imprimatur of an occupying force. Iran appears to rely primarily on less formal agreements with Shia powerbrokers in Iraq. It only recently renewed its military cooperation agreement with Damascus.⁶⁵

In each case, the role and legal authorities of security forces in the constitutional order of a state engaged in active combat either with an external or internal adversary thus proves pivotal in demarcating the difference between a proxy strategy that employs “allies,” “partners,” or “surrogates.” The lines may not always be bright, but since one of the main purposes of a constitution is to define the terms of the social contract between a government and its citizens for the provision of internal and external security, examining the legal authorities different forces operate under becomes critical to understanding parameters of proxy strategies.⁶⁶ In weighing the costs and the benefits of clientelist proxy strategies that augment existing forces operating under a clearly articulated constitutional mandate versus irregular forces outside that mandate, a key consideration is how either choice impacts the perceived legitimacy of the state and drives up the cost of doing business for sponsors.

The decline in inter-state conflict and prevalence of civil wars since the collapse of the Soviet Union suggests that proxy forces will remain an attractive tool for exerting strategic influence. Since irregular forces are rarely, if ever, mentioned or explicitly described in the constitutions of most states, the strategic usefulness of irregular forces to third parties—be they states or non-state actors—is the very ambiguity of their authorities. It is also in that ambiguity that the classic principal-agent problems of moral hazard and adverse selection challenges often arise.⁶⁷ Adverse selection occurs when the expert knowledge that makes proxy forces so attractive to sponsors is used to pursue hidden objectives that may not align with those of sponsors or alternatively when sponsors use proxies to pursue goals that remain hidden from the proxy (often this is seen in sudden changes in sponsor policy, with sponsors abandoning proxies to achieve broader foreign policy goals).

The inability to constrain proxies from abusing power or bending norms around the principals of distinction, proportionality, and military necessity that undergird International Humanitarian Law (IHL) creates a moral hazard for sponsors who championing the political claims of one combatant group over another. Sponsors may pay a high price from the “strategic costs of civilian harm”⁶⁸ arising from murky command and control arrangements that exact tolls on the very population military actions are meant to protect, but which the proxy is not affected by because external sponsorship has shielded the agent from popular backlash.⁶⁹

The potential for conflict escalation can be high in proxy warfare as a result of the challenges described above. Absent the constraints of well-defined authorities and clear command and control structures, agents may be incentivized to take more risks on the battlefield, raising the risk of conflict escalation.⁷⁰ At the same time, the local expertise that makes proxies so attractive and expedient to external sponsors may also motivate proxies to hide information from sponsors about the actual costs and risks of battlefield tactics.⁷¹ High risks and hidden information can make it more difficult to broker an end to conflict, since populations at the mercy of proxies may be less inclined or incentivized to accept a deal that entails power-sharing with former adversaries, or that fails to bring perpetrators of atrocities to account. The nearly 50-year-long conflict in Afghanistan—with its many failed power-sharing deals—is a case in point, while the conflict in Syria certainly seems to be moving onto a similar track.

The local expertise that makes proxies so attractive and expedient to external sponsors may also motivate proxies to hide information from sponsors about the actual costs and risks of battlefield tactics.

Despite these drawbacks, reliance on irregular forces offers strategic advantages that some sponsors may calculate outweigh potential downsides, providing three key benefits. First, it insulates sponsors from the high risks and costs associated with direct military action while allowing them to tap into local coercive power unconstrained by international or local customary law. Second, it obscures the express or implied terms of the contract between sponsoring principals and their proxy agents from public scrutiny, which has the added benefit of allowing sponsors to bend, break, or reshape established norms without suffering immediate retribution from adversaries. The less is known about the ways and means that irregular forces enable sponsors to remotely target and disrupt the activities of their rivals, the greater the degree of strategic surprise. The same might be said of allied or aligned conventional forces who, by express agreement, advance the strategic interests of another state by conducting expeditionary operations. Third, support for proxies arguably also allows sponsors to challenge rivals for a longer duration, since domestic responses to military intervention through third party forces is frequently met with public indifference, or even outright support, as long as it does not entail domestic conscription or casualties.

Proxy warfare is best defined as the direct or indirect sponsorship of third-party conventional or irregular forces that lie outside of the constitutional order of states engaged in armed conflict. Secrecy, plausible deniability, and ambiguity in the rules of engagement and command structure are characteristic features critical to the success of proxy strategies, making narrative control over the quality of command and control a central tactical concern. Yet the more obscure the connections between command and control and the more covert the proxy networks, the less visibility sponsors have into whether and when proxies are operating on agreed terms and providing verifiable information about conditions on the ground.

Existing definitions of proxy warfare each grasp part of this problem, but some are too broad, like Mumford’s suggestion that when the actions of a third-party unintentionally serve the strategic interests of a stakeholder with interests in a conflict. A vision of proxy warfare that includes traditional coalition warfare or allied support, where command and control and rules of engagement are articulated under formalized agreements, mistakenly conflates the characteristics of alliance dynamics with the features that make proxy warfare such an alluring, but also dangerous, policy choice.

There is a real risk that overly elastic definitions could contribute to an escalatory climate by encouraging military responses to perceived threats from armed groups that are not actually part of a sponsor’s proxy strategy. This question has particular policy relevance when it comes to the Trump administration’s assertion that al-Qaeda is an Iranian proxy as justification for withdrawing from the Iran nuclear deal. Tehran’s relationship with al-Qaeda is contested at best, and there is substantial evidence that suggests Iran’s interactions with al-Qaeda were often hostile.⁷² A legalistic focus avoids such overly broad definitions of proxy warfare that stretch the term beyond useful meaning. It helps clarify disputes over what constitutes proxy sponsorship by linking the definition to the provision of material support to combatants that enhances their lethality.

As noted above, there will always be debate over where to draw the line. For example, is Syria’s attempt to formally integrate Iranian-backed militias operating in the country a legitimate legal authorization? Is Yemeni President Abdrabbuh Mansur Hadi’s invitation to the Saudi coalition to intervene in Yemen truly authorizing the activities of the coalition, and does this continue to hold legal sway given the collapse of governance in the country?⁷³ Similar debates exist regarding the militias active in Iraq, where assessing the various levels of legal integration into the Iraqi system helps clarify the challenges posed by militias.⁷⁴ Despite sometimes blurry distinctions, a definition that looks to international law provides a basis for resolving or at least assessing claims regarding where particular cases fall even if debate over proper interpretation persists.

Proxy warfare is best defined as the direct or indirect sponsorship of third-party conventional or irregular forces that lie outside of the constitutional order of states engaged in armed conflict.

A legal definition also enables the examination of private military companies and militias that may be understood by a sponsor as augmenting its forces, rather than replacing them. Rather than getting bogged down in debates over whether a strategy augments or replaces forces—as Pfaff’s definition risks doing—a legal definition shifts the focus to whether a group is a third party operating under an unbroken chain of constitutional authority. This is essential, for example, when it comes to evaluating whether Russia is waging proxy warfare via private security that are deeply tied to the state but also often outside the country’s formal armed forces and in the case of non-western countries’ reliance on militias, an issue raised well by Ahram.

A legal definition also avoids the artificial limits of state-centric definitions, such as that put forward by Hughes requiring that proxy warfare involve a state sponsor supporting a non-state group. It enables scrutiny to be applied to cases where states sponsor other states in wars that exist outside of—or purposefully stretch the meaning of—constitutional authorizations. For example, the United States’ support for the Saudi coalition in Yemen can be analyzed under this framework if the Saudi-led coalition is judged to be acting outside of constitutionally authorized structures in Yemen. Similarly, non-state sponsors, whether powerful individuals or organizations, should not be excluded from an effort to address the dangers of proxy warfare strategies by dint of their not being states.

A legal definition focused on constitutional authorization and international humanitarian law holds promise for policy development to return accountability to and limit the costs imposed by today’s proxy wars without being sidetracked by politicized and analytically unsound accusations, where only one’s rival’s partners are proxies. A more stable reference point based in law as to what constitutes proxy warfare helps guide policy debates about the efficacy and wisdom of partner operations and gives local populations, human rights advocates, and peace activists a tool with which to identify and clarify the lines of command, a prerequisite to any semblance of democratic governance and accountability in warfare.

As the U.S. experience in Afghanistan and Iraq illustrates, adverse selection problems have real-world consequences of joint or partnered military operations, detentions, and intelligence sharing. In Afghanistan, several major military operations resulting in mass casualties have been directly attributed to faulty intelligence provided by Afghan forces to their American military partners.⁷⁵ In some cases, Afghan forces deliberately fed misinformation to their American and NATO counterparts with the express purpose of eliminating rivals; in others, inaccurate information was provided to deliver a short-term tactical advantage where Afghan forces were unable to overcome their adversaries without coloring outside the lines of international humanitarian law. The October 2015 bombing of a hospital run by Doctors Without Borders in the northern province of Kunduz is perhaps one of the more striking cases in which misdirection and misinformation provided by Afghan forces resulted in devastating numbers of civilian casualties and heavy collateral damage.⁷⁶ In Iraq, faulty intelligence provided by local partners on the ground has reportedly resulted in a persistent pattern of errant strikes.⁷⁷ Several high-ranking U.S. military officials have openly admitted to the strategic costs of errant strikes⁷⁸ and false intelligence provided by local partners, resulting in substantial changes to the ways partnered operations are handled.⁷⁹

If Russian operations in Syria and Ukraine are any guide, Moscow appears even less concerned about the adverse selection problems and the strategic tradeoffs of backing the Assad regime and other proxies on the ground. As seen with skirmishes in Deir Ezzor between U.S. forces and proxies in the Wagner Group, a Russian private military security company (PMSC) with alleged Kremlin connections, reliance on proxies raises the real risk of escalation.⁸⁰ In Ukraine, the downing of the commercial jet MH17 in July 2014 is another instance in which faulty targeting by proxies on the ground had real strategic impact.⁸¹ Moscow, for its part, appears to have developed a systematic strategy of disinformation about operations in which its forces may have been involved, suggesting that one of the best routes for measuring the extent of its control over proxies in Syria and Ukraine may be in examining patterns of denial.

Often the covert nature of connections between sponsors and their proxies, and lack of transparency about the rules of engagement in partnered operations, may provide tactical advantages. But, as seen in the cases of U.S. operations in Afghanistan and Iraq, and Russian operations in Syria and Ukraine, persistent monitoring of proxy activity may be the only way to measure the effectiveness of proxy strategies. Four factors warrant examination when defining terms of reference for proxies: authorities, territoriality, alignment with stated sponsor goals and objectives, and information discipline. But once a proxy strategy is defined, what exactly constitutes a sponsor’s control or influence over a proxy, and how can control be measured so that it can be applied more effectively?

As Ladwig explains, aid dependence, power asymmetry, selectorate theory,⁸² and the strategic utility of a client state make up the main competing theories of control in the academic literature.⁸³ None account for the often divergent interests between patrons and client state powerbrokers who often are poorly incentivized to comply with externally imposed policies, lest they look weak to their neighbors and vulnerable to their domestic rivals and constituents. The fractious relationship between successive White House administrations and the government of Hamid Karzai, the former president of Afghanistan, is one more recent example of this phenomenon.⁸⁴ But in strategy, as in other realms, past is precedent. In this regard, the history of the Cold War and the two decades that followed the collapse of the Soviet Union in the lead-up to 9/11 are even more instructive.