International Law, Political Will, and Regulation of the Foreign-Fighter Phenomenon
Editor’s Note: This post is based on an article, “Regulating the Foreign-Fighter Phenomenon” published in the Virginia Journal of International Law, available here.
Across at least three centuries, foreign fighters—individuals who voluntarily depart their countries of origin to participate in armed conflicts abroad—have been a persistent and recurrent phenomenon. They have fought for States and for non-State organized armed groups in both international and non-international armed conflicts. In some cases, they have been force multipliers, providing skills and expertise otherwise lacking in the armed forces they join. In others, they have been little more than cannon fodder. And, although they have been closely associated with jihadists in recent decades, historically, foreign fighters have supported causes spanning the political spectrum.
Despite their frequent appearance on battlefields around the world, the international community has generally treated each manifestation of the foreign-fighter phenomenon as sui generis. To the extent that the international community has responded to foreign fighter mobilizations, it generally has done so in an ad hoc and context-specific manner. But with each manifestation, the phenomenon itself materially and normatively challenges the international order. Additionally, with each manifestation, the phenomenon carries the seeds of its own recurrence through fighters’ transnationalization, the training and combat experience they accrue, and their embedding in networks of likeminded comrades. They are, thus, a free-floating threat to international security; and the phenomenon itself undermines States’ monopoly on the use of force and the structural assumptions of the international legal order.
The Foreign Fighter Phenomenon Today
Today, the approximately 2,000 foreign fighters from more than fifty countries in Syrian Democratic Forces’ (SDF) custody in northeast Syria are the single largest concentration of terrorists in the world. They represent a substantial portion of the remnants of the Islamic State in Iraq and Syria (ISIS), captured primarily in the final phase of the territorial defeat of the so-called ISIS caliphate. These fighters and their comrades did not mobilize, coalesce, train, or fight in a vacuum. Many benefited from transnational facilitation networks, forged in the crucible of armed conflicts in Afghanistan between 1979 and the 2000s, Iraq during the 2000s, and the former Yugoslavia in the 1990s. Many benefited from training camps that were modeled on earlier training camps with curricula that innovated in the shadow of previous fights. Some may have been led by veteran foreign fighters.
Although the continued confinement of the foreign fighters in SDF custody is precarious and uncertain—and although they pose individual and collective threats to the international community—their States of origin have been markedly reluctant to effect their repatriation. This failure not only deprives the victims of foreign fighters’ unlawful acts the justice to which they are entitled, it threatens the security of the region, the international community, and the States of origin themselves.
The continuing failure of States of origin to take responsibility for their detained nationals raises political, diplomatic, and security questions. It also raises legal ones. Primarily, how can international law tolerate this insecurity and irresponsibility?
Toward International Regulation of the Foreign-Fighter Phenomenon
In a recent article in the Virginia Journal of International Law, I argue that international law could better promote international security by regulating the foreign-fighter phenomenon in a manner that clearly assigns to States of origin the responsibility of both restraining the transnational mobilization of their nationals and recovering, in certain circumstances, those of their nationals who nevertheless become foreign fighters. Such international legal regulation of the foreign-fighter phenomenon would remove the seeming discretion of States of origin to tolerate the mobilization of their nationals as foreign fighters. It would also remove the apparent discretion enjoyed by States of origin in choosing whether and when to repatriate their nationals who become foreign fighters.
Building on existing legal, international relations, and political science scholarship, I begin by defining foreign fighters—a category of individuals that currently escapes formal definition at international law—as (1) individuals who leave their State of origin (2) to join a party other than their State of origin that is engaged in an armed conflict (3) in a State in which the individuals are aliens (4) at their own initiative and (5) who are not mercenaries under international law.
Significantly, this definition is value neutral, rejecting ultimately counterproductive and discriminatory efforts to describe foreign fighting in ideological terms or by focusing on the tactics foreign fighters may adopt in the future. The definition then sets the parameters of the problem by describing the life cycle of foreign fighters, identifying the departure and return phases of that life cycle as critical to addressing the problems the phenomenon poses.
These phases are of primary importance to international security and any prospective international legal regulation because they represent the moments at which the international security threat posed by foreign fighters are realized. In the first instance, departure represents the moment when would-be foreign fighters embark on transnational fighting, threatening the security of the territorial State(s) of any conflict zone. The return phase, on the other hand, is the moment when States may adopt policies that tend to encourage or compel foreign fighters to not just remain abroad but to travel to additional conflict zones, thereby propagating the international insecurity they represent. Importantly, because both phases implicate the relationship between States of origin and their nationals, they suggest that States of origin are the most appropriate entities in the international community to restrain the proliferation of foreign fighters.
Regulating the Departure Phase
I contend that international law could effectively regulate the foreign-fighter phenomenon by extending existing due diligence principles of international law to the departure phase of their life cycle. Arguably, the principles of non-intervention and harm prevention already impose obligations on States that should prohibit them from knowingly tolerating their nationals from becoming foreign fighters. The principle of non-intervention prohibits States from intervening directly or indirectly in the internal or external affairs of other States. Thus, subject to the limitations of their capacity, States of origin may not knowingly tolerate subversive or armed activities “directed towards the violent overthrow of the régime of another State.”
General public international law likewise requires States to exercise due diligence to prevent their territory from being knowingly used in a way that is harmful to another State. Together, these principles should require States of origin to interrupt the knowing departure of their nationals to participate in foreign armed conflicts, the first stage in the foreign-fighter lifecycle. Such an obligation is seemingly corroborated by—or at least consistent with—neutrality law, which “establishes rules to guarantee to belligerent [S]tates that neutral [S]tates will not permit their territory to be used by another belligerent as a safe harbor or a place from which to launch attacks,” including by non-State organized armed groups.
Despite these principles, historically, States of origin have repeatedly tolerated their nationals becoming foreign fighters when doing so has served those States’ domestic or foreign policy interests or objectives. For example, during the anti-Soviet jihad, a number of Arab States tolerated or even encouraged their nationals to join the transnational mobilization of the so-called Arab Afghans to fight the Soviet Union in Afghanistan. While these fighters played a de minimis role in the defeat of the Soviet Union, the experience they earned, the training they received, and most importantly the networks in which they embedded reverberated across conflict zones as diverse as the former Yugoslavia, Chechnya, Afghanistan following the U.S. invasion in October 2001, Iraq following the U.S. invasion in 2003, and Syria during the civil war which began in 2011.
The extension or clarification of existing international law with respect to foreign fighters would promote international security and the international order by limiting States’ discretion to pursue unfriendly public policy through their tolerance—or even willful ignorance—of apparently private behavior. It would do so by establishing a clear legal obligation not to tolerate such behavior with respect to foreign fighting and by imposing legal costs on States that fail to abide by that obligation.
Regulating Repatriation
Additionally, I argue that the imposition of international legal obligations on States of origin concerning the repatriation of their nationals from foreign conflict zones could restrain the subsequent propagation of the foreign-fighter phenomenon to additional armed conflicts.
Existing principles of international law already imply an obligation on the part of States of origin to repatriate their nationals from foreign armed conflicts in certain circumstances. International humanitarian law (IHL) implies that States of origin must repatriate their nationals who participate in foreign armed conflicts, irrespective of the character of those armed conflicts, at least in certain circumstances. For example, in international armed conflicts, IHL implies that States of origin must accept the repatriation of their nationals who have become prisoners of war (POW) by imposing an obligation on detaining powers to repatriate POWs without delay upon the cessation of hostilities.
Less clearly, in non-international armed conflicts (NIAC), to the extent that IHL accepts the conflict-based detention of individuals, that detention must cease with the termination of the relevant NIAC lest it become arbitrary and unlawful. When aliens are deprived of their liberty during a NIAC, it is reasonable to infer that detaining authorities incur a post-conflict obligation to repatriate them. Moreover, in the non-conflict context, international law requires that States of origin repatriate their nationals upon deportation. Together, these principles suggest that States of origin are not relieved of their responsibilities vis-à-vis their nationals by their mere departure to participate in a foreign armed conflict.
Finally, an obligation to repatriate nationals who become foreign fighters would be congruent with States’ overarching obligation to “make full reparation for the injury caused by [an] internationally wrongful act” (art. 31). Full reparation entails “as far as possible, wip[ing] out all the consequences of the illegal act and reestablish[ing] the situation which would, in all probability, have existed if that act had not been committed.” Assuming that tolerating the departure of their nationals is an international wrong, repatriation is at least a natural first step toward restoring the status quo preceding their participation in a foreign armed conflict. It would, thus, represent a partial reparation for the harm inflicted on the victim State by the State of origin’s malfeasance.
Ultimately, my argument is modest. It draws a logical conclusion from the application of several international legal principles to a historically recurrent, if under theorized, international phenomenon. It suggests that, as a matter of law, States do not enjoy as much discretion as it often seems regarding the departure or recovery of their nationals who become foreign fighters. Clearly extending these legal principles to the foreign-fighter phenomenon would improve international security by restraining the phenomenon’s recurrence and prolongation.
International Political Will and Its Assumed Absence
Skeptics of my argument are likely to object to its viability on the basis of a perceived absence of international political will to regulate the foreign-fighter phenomenon. This is a significant objection. The fact that the phenomenon has recurred across diverse historical eras and a variety of ideological fissures suggests that the international community may not possess the political will to regulate the phenomenon. Indeed, the seeming willingness of diverse States of origin to tolerate the transnational mobilization of their nationals over three centuries in order to achieve domestic or international policy objectives may evidence the perceived absence of international political will to regulate it.
But a closer look at the international community’s historical record indicates that there may be greater political will in this context than is often assumed. In fact, the international community has repeatedly attempted to regulate the foreign fighting. It attempted to do so during the Spanish Civil War. It did so in the peace agreement that ended the armed conflicts in the former Yugoslavia. And, arguably, it attempted to do so in the peace agreement that ushered the Soviet Union’s withdrawal from Afghanistan with specific reference to the principle of non-intervention. Unfortunately, these efforts were ad hoc and sui generis; they were explicitly tied to those conflict contexts and provided the international community with no legal tools to address foreign fighting in the future.
More recently—and more hopefully—the international community has adopted a prospective, general legal architecture for regulating at least one species of foreign fighting: foreign terrorist fighters. Acting under Chapter VII, the UN Security Council has adopted a series of resolutions, beginning with 2170 (2014) and 2178 (2014) intended to restrain foreign terrorist fighting irrespective of the conflicts in which these fighters participate. These resolutions impose obligations on States of origin that address both the departure and return phases of the foreign-fighter life cycle.
Unfortunately, drafted and adopted against the backdrop of the rise of ISIS, these resolutions counterproductively predicate States’ legal obligations on terrorism, a term the resolutions leave undefined. Consequently, the resolutions articulate a legal architecture that is both under inclusive and subject to States’ potentially ideologically motivated interpretations of “terrorism.” Notwithstanding their deficiencies, these UN Security Council Resolutions are clear evidence of the international community’s willingness to develop international legal tools to redress the international insecurity presented by foreign terrorist fighters.
Conclusion
As Thomas Hegghammer has observed, “Foreign fighters matter because they can affect the conflicts they join.” They do so by providing personnel, skills, experience, training, or leadership to the parties they join. They have done so independent of ideological motivations in diverse historical eras and across three centuries. Throughout that period, foreign fighters have acted as self-initiated and self-constituted forces that challenge States’ sovereign prerogative to use force, subject to international law. And, throughout that period, each manifestation of the foreign-fighter phenomenon has carried with it the seeds of the phenomenon’s recurrence.
From British veterans of the Napoleonic Wars augmenting Latin American revolutions, to veterans of the i Mille in the wars of Italian unification joining the revolution in Poland, to veterans of the Spanish Civil War joining the Israeli War of Independence, to Arab Afghans joining the fight in the former Yugoslavia and beyond, the networks in which foreign fighters embed reverberate in subsequent armed conflicts for years and decades to come, spreading local, regional, and international insecurity.
Irrespective of the quality of the cause to which foreign fighters adhere, they are a host unto themselves. By imposing clear obligations on States of origin to restrain the transnational mobilization of their nationals, international law can and should bolster international security by raising the legal costs of such States’ tolerance of foreign fighters. It should likewise demand that in certain circumstances, States of origin repatriate their nationals who become foreign fighters to dampen the prolongation and recurrence of the foreign-fighter phenomenon.
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Benjamin R. Farley is a Visiting Fellow at Emory University School of Law and Acting Director of the U.S. Department of State’s Office of Terrorist Detentions. The views expressed herein are solely those of the author and do not necessarily reflect those of the U.S. Government.
Photo credit: Pexels
