Three Lingering Questions about the Legality of Withdrawal from Syria: Part II – Duty to Ensure Respect & Releasing ISIS Detainees

[Beatrice Walton is a 2018 graduate of Yale Law School and served as Judicial Fellow at the International Court of Justice in The Hague in 2018-2019. Paul Strauch graduated from Yale Law School in 2018, where he was a Herbert J. Hansell student fellow at the Center for Global Legal Challenges and Editor-in-Chief of the Yale Journal of International Law. This is the second part of a two-part series on the U.S.’ withdrawal from Syria. Part I can be found here.]

When Do Common Article 1 (Duty to Ensure Respect) Obligations End?

Prior to the U.S.’ decision to withdraw its forces from Syria, commentators, including the UN Human Rights Council’s Independent International Commission of Inquiry on the Syrian Arab Republic, had observed that under Common Article 1 of the Geneva Conventions, States had a “duty to ensure respect for IHL” by the non-State actors with whom they were collaborating. At least one commentator noted as much in the context of U.S. collaboration with Kurdish forces in the fight against ISIS specifically. As a result of this relationship, the U.S. was understood to have taken on an obligation to ensure, in particular, that the SDF — which has been holding tens of thousands of persons in detention (in some cases, for several years) — did so in accordance with IHL. As is well-known, both State and non-State actors are obligated to obey IHL rules concerning detention conditions and respect the prohibition against arbitrary detention in non-international armed conflicts.

But was the U.S. still obliged to ensure the conditions of these detainees as a result of this duty even after it decided to withdraw its forces? The short answer is maybe. Commentators often focus on the importance of control in determining the content of the duty, which could suggest that the duty becomes de minimis in the event of a withdrawal. However, the foreseeability of IHL violations, and the capacity of a State to influence them, also matter, and may have worked to impose on the U.S. an obligation to work to prevent these harms. 

The Scope of Common Article 1 – The Relevance of ‘Control’ Factors

The scope and application of Common Article 1 — which obligates States to “undertake to respect and to ensure respect” for the Geneva Conventions — has long been debated. Gradually, the view that Common Article 1 is only aspirational has given way to the view that the Article imposes binding legal obligations. In Nicaragua (paras. 219-20, 255), the ICJ found the U.S. liable under this Article, and in the Wall Advisory Opinion (paras. 156-60), the Court arguably indicated that Common Article 1 imposes some positive due diligence obligations. The International Committee of the Red Cross (ICRC) has also specified the content of the obligation. In its 2016 Commentary, the ICRC explains that Common Article 1 requires that States “neither encourage, nor aid or assist in violations of the Conventions,” (para. 154) as well as act positively to “prevent violations when there is a foreseeable risk that they will be committed and . . . prevent further violations in case they have already occurred.” (para. 164). As part of the obligation to take positive action, States must ensure compliance with IHL not only by their own forces, but also by other parties to a conflict, including non-State parties.

Accepting the view that Common Article 1 applies to States in their interactions with non-State actors, when are such obligations no longer be relevant? On its face, Common Article 1 seems to be clear: the obligation to ensure applies “in all circumstances.” This means, according to scholars and the ICRC, that the obligation applies even to States not participating in a particular conflict, and even in times of peace. (ICRC Commentaries at paras. 127-129, 185).

Disagreements have unsurprisingly emerged over what Common Article 1 concretely entails, particularly for third States not otherwise involved in a conflict, even if it can be said to in some sense always apply. Most commentators, as well as the ICRC, have embraced an interpretation according to which the extent of a State’s obligation to ensure respect depends on its relationship to the violating State, or characteristics of the violation itself. The ICRC’s 2016 Commentaries suggest that Common Article 1 functions like a sliding scale for third States: the more control the third State exercises in relation to another actor, the greater the obligation by the State to ensure IHL compliance by that actor. As the Commentaries explain, States which engage in “financing, equipping, arming or training” other armed forces, or which “even plan[], carr[y] out and debrief[] operations jointly with such forces,” take on a “unique position to influence the behaviour of those forces, and thus to ensure respect for the Conventions.” (para. 167).

Commentators have recognized that control need not rise to the level of that required for State responsibility, but a focus remains on some form of connection between the State and the violating forces. Tomasz Zych, for example, has indicated that the scope of the duty depends on whether the State is “in fact directing or controlling the [other] persons in questions.” Birgit Kessler has underscored that a “State’s obligation under Article 1 to take further steps to ‘ensure respect’ of the Conventions by stopping the violation of [IHL] depends on the State’s influence on the breaching party.” Recently, Common Article 1 has been invoked in the context of U.S. support for the Saudi-led coalition in Yemen, where financial and technical support for the breaching actor has been high.

The Importance of ‘Foreseeability’ and ‘Capacity to Influence’ Impending IHL Violations

The U.S. withdrawal from Syria, after supporting Kurdish allies in their detention operations, puts into sharp relief the importance of other elements in determining the scope of Common Article 1. Indeed, as the decision to withdraw was made while the U.S. still had an ongoing partnership with the Kurds, a strict view of the importance of the ongoing relationship between a State and violating actors would imply that the U.S. absolved itself of any Common Article 1 duty to guard against IHL offenses by the SDF. (To be sure, other obligations under human rights law directly are also relevant, though outside the scope of this piece). Recognizing this is important because the literature remains unclear as to the scope of such a duty where a State retains minimal, or even no, connection or control vis-a-vis the breaching party, but where a violation by that party is nonetheless foreseeable.

Under a conception of Common Article 1 that recognizes a State’s involvement in a conflict as relevant to curtailing an overly-broad reading of the obligation, “foreseeability” and “capacity to influence” potential IHL violations should be regarded as key determinants of whether a State has a duty to ensure respect under Common Article 1. In explaining that the U.S. retained an obligation to ensure respect for IHL by non-State actors supported by the U.S., the ICJ articulated in Nicaragua that “it is material to consider whether th[e] encouragement was offered to persons in circumstances where the commission of

[unlawful acts]

was likely or foreseeable.” Hathaway et al. have argued that, when taken in combination with Nicaragua, the ICJ’s Wall Advisory Opinion — which read Common Article 1 as embracing positive duties — suggests that third States may be “liable for their failure to take preventative action against foreseeable IHL violations by other States.” Outside the Article 1 context, the ICJ has observed that the scope of a State’s due diligence obligation depends on the State’s “capacity to influence” a certain situation. The 2016 ICRC Commentaries seem to suggest a similar standard. (paras. 150, 164).

The facts bear out the problems of failing to adequately look to foreseeability in determining the content of a State’s ensure respect obligation. At the time of withdrawal, the SDF had been detaining over 11,000 ISIS men, and managing camps holding tens of thousands of more women and children. Since the U.S.’ withdrawal, these prisons and detention centers have deteriorated. Hundreds of ISIS detainees have escaped. Where camps holding women and children disintegrate, those released may be placed at risk of reprisal attacks, as well as detention by the Syrian regime where they could face torture, sexual violence, or execution. And even as the issue of repatriating the tens of thousands of individuals held in detention has been raised for some time, the U.N. Special Rapporteur on the Promotion and Protection of Human Rights and Fundamental Freedoms while Countering Terrorism recognized that the situation took on urgency in the wake of the U.S.’ decision to withdraw. Further concerning is the possibility of IHL violations by released ISIS fighters who rejoin the conflict.

It strikes uncomfortably that as the U.S. began withdrawing, these harms were largely foreseeable, in part because many of the IHL violations stemming from the indefinite detention of such large numbers of persons — in circumstances some have described as “arbitrary” — were ongoing prior to the withdrawal. Further, SDF commanders had notified U.S. officials that a U.S. withdrawal and Turkish invasion could force them to divert attention from managing detention centers. Others had warned that doing so would lead to compromised SDF prison security.

What might the U.S. have done? The ICRC explains that under Common Article 1, States are to “do everything reasonably in their power to ensure respect.” While that may sound overly onerous, commentators suggest options for meeting this standard far from military action. These include diplomatic pressure and exercise of “moral suasion” and influence on one side, and more coercive measures on the other. As noted in our first post, it is true that the number of troops needed to have halted the Turkish advance is unclear, and the advance was arguably inevitable. Still, some financial and technical support to assist the detaining authorities might have been warranted, and reports suggest that further diplomatic options might have been available.

Ultimately, our takeaway is simple: When a State involves itself in partnerships with other State- and non-State actors, thereby incurring a duty to ensure that this partner abides by IHL requirements, it cannot expect to be entirely dissolved of responsibility for foreseeable harms that follow as that relationship winds down.

A Duty to Prosecute – Is Anyone Responsible for Releasing Detained ISIS Fighters?

A final question raised by the U.S.’ decision to withdraw is who, if anyone, might be responsible for the freeing and release of the at least 100 ISIS fighter suspects previously in detention.

As previously indicated, prior to withdrawal, Common Article 1 required that the U.S. ensure compliance by the Kurds with respect to their detention of ISIS fighters. Whether IHL authorizes trials by non-State forces remains disputed. Under one perspective, whether IHL authorizes particular non-State actors to establish courts to prosecute war crimes depends on the group’s level of organization and competence. This argument follows the “sliding scale” approach to non-State IHL obligations, according to which the better organized an armed group is, the more applicable IHL rules become for it. By contrast (p. 782), others contend that the principle of belligerent equality implies that non-State actors are generally authorized to form courts based on their own regulations. 

Given this disagreement, even before the withdrawal, the authority of the Kurds under IHL to prosecute ISIS fighters was uncertain, with differences remaining over whether the YPG and PYD (the main political group in Kurdish-held territory and political arm of the YPG) would qualify as sufficiently organized and institutionalized to establish courts. In any event, undisputed is that any courts formed by the YPG for trying war suspects were required to be “regularly constituted,” according to Common Article 3. Other Geneva Convention provisions, combined with the Additional Protocols, further insist that courts be independent, impartial, and afford basic guarantees. Overall, the resource-strained Kurdish courts appear to have fallen short (even as they have adopted some progressive-leaning practices). Courts in Kurdish-held territory have been characterized as lacking in independence from the PYD, and in need of qualified judges. Significant criminal process concerns have also surfaced as individuals have been tried without access to lawyers or on the basis of confessions.

But what is perhaps surprising is that it is not obvious that the Kurds had an obligation to prosecute ISIS fighters, or investigate possible war crimes — even presuming that they were authorized to hold trials. According to the ICRC, while States are always under a duty to investigate and prosecute war crimes, the same is not necessarily true of non-State actors. Rule 158 of the ICRC’s customary international law study — which sets forth a duty to investigate war crimes, and, if appropriate, prosecute perpetrators — refers only to States. It requires that States investigate war crimes committed either on their territory or by their nationals (or perhaps by persons over whom the State exercises universal jurisdiction). Admittedly, some limited recent practice indicates that non-State actors controlling territory might have an obligation to investigate and prosecute. For instance, the Goldstone Report (p. 509) found that any de facto authority that has government-like functions is under a duty to prosecute. But on the whole, support for a requirement incumbent upon the Kurds to set up courts and prosecute crimes committed by other parties is lacking. (Notably, YPG leaders may still be required to conduct trials of their own subordinates consistent with the doctrine of command responsibility.)

The two factors set forth in Rule 158 — territory and nationality — do nonetheless suggest that Syria and Turkey retain an obligation to prosecute ISIS suspects. But as neither factor applies to the U.S., it is seemingly absolved of responsibility. (Still, the U.S. has undertaken some efforts towards ISIS accountability, such as by removing two “high-value” detainees for prosecution in the U.S. or U.K.)

However, even where States, like the U.S., do not hold ISIS detainees directly, they may not be completely off the hook. In Resolution 2396 (2017), the UN Security Council reiterated that “all Member States shall ensure that any person who participates in the financing, planning, preparation or perpetration of terrorist acts or in support of terrorist acts is brought to justice.” This obligation is not as obviously limited with respect to territory and nationality as Rule 158, even as States have seemed to interpret it as such.

Pulling these strands together, who retains legal responsibility for ensuring the ISIS fighters in Kurdish detention are investigated and prosecuted remains a bit of a legal gray area. As the release of ISIS detainees in the wake of the U.S. withdrawal has underscored, there remains an urgent need for States to take measures to address the security and humanitarian issues associated with the detention of ISIS suspects by non-State actors. Options include the creation of international tribunals (as the Kurds have been advocating since at least last winter) and repatriating war criminals to States where they can face an appropriate legal process.