In this post, I want to evaluate the link between two contemporary foreign policy issues that are generally viewed as unrelated. The first is ongoing U.S. military assistance to Syrian rebels. As Reuters reported last week, the United States is currently supplying a variety of small arms, anti-tank rockets, and other items to “moderate” rebel factions, and Congress has approved funding for future deliveries through the end of the fiscal year. The second issue is the Obama Administration’s decision to sign the Arms Trade Treaty (“ATT”) last September. While it’s far from clear that the United States will ratify the ATT, an established doctrine of international law holds that the act of signature triggers an interim obligation to refrain from conduct that would defeat the treaty’s “object and purpose.” This obligation might restrict the ability of the United States to supply arms to the rebels, and raises questions about the legality of the ongoing transfers. To understand why, it’s necessary to consider the text of the ATT, the rebels’ conduct, and the nature of the interim obligation.

First the ATT. Designed to regulate the global trade in conventional weapons, the treaty’s major features include a restriction on transfers linked to international crimes, recordkeeping and reporting requirements, and a mandate to regulate brokering. With respect to the situation in Syria, the key provision is Article 7, which prohibits a state-party from authorizing an export when there is an “overriding risk” that the arms “could be used to . . . commit or facilitate a serious violation” of international humanitarian or human rights law. A state-party decides for itself whether the danger of illegal use is sufficiently high, but must do so in an “objective and non-discriminatory manner, taking into account relevant factors,” including possible means of risk-mitigation.

It’s plausible that arms shipments even to “moderate” rebels would violate Article 7 if the United States were a party to the ATT. In a series of reports over the last two years, the Independent International Commission of Inquiry on Syria has documented numerous instances of anti-government forces committing serious violations of international humanitarian and human rights law, including extrajudicial executions, hostage-taking, attacks on civilians, and torture. Extremists such as the al Nusra Front have committed many of these acts, but the lines of separation between the various rebel groups are blurry. The Commission has reported, for example, that rebel fighters shift between Salafist factions, the Free Syrian Army (“FSA”), and other armed groups based on the availability of funds and weapons; that the FSA and independent groups have cooperated on the battlefield; and that the intensity of the fighting has led to a general radicalization among anti-government forces. What’s more, the Commission has identified the direct involvement of even comparatively moderate FSA rebels in the torture and execution of government soldiers. Given the pattern of violations on both sides, the intensity of the mutual animosity, and the apparent difficulty of channeling weapons exclusively to preferred groups, it’s not unreasonable to think that there’s a significant risk U.S. arms will be used to commit or facilitate serious violations of international law. Indeed, that risk may be overriding.

If the arms deliveries would violate Article 7, the question becomes whether they are unlawful in light of America’s current status as a mere signatory. Put differently, does conduct that would violate a treaty necessarily violate the interim obligation not to engage in conduct that defeats the treaty’s object and purpose? Or does signatory status permit the United States to act in a way that’s prohibited among states-parties? Unfortunately, international law is not terribly clear on the subject, and commentators have offered a number of conflicting views. Some argue that the interim obligation only prohibits acts that would “substantially undermine” the ability of other parties to comply with or benefit from the treaty after ratification. Others contend that the law proscribes conduct carried out in bad faith. Still others claim that the interim obligation precludes behavior that transgresses a treaty’s “core” or “essential” provisions.

These variations make it hard to reach any firm conclusions about legality. On one hand, the shipments don’t appear to prevent other ATT parties from complying with their own obligations or benefitting from the treaty. Nor is there evidence that the United States is acting in bad faith; if anything, the decision to supply arms only to “moderate” rebels shows that U.S. officials are making efforts to ensure that the weapons are not involved in international crimes. On the other hand, Article 7 is plainly one of the ATT’s most important provisions, given the treaty’s purposes of “contributing to international and regional peace, security and stability; reducing human suffering; and promoting cooperation, transparency and responsible action by States Parties in the international trade in conventional arms.” A narrow reading of the interim obligation seems to permit the U.S. deliveries, while a broad reading has the opposite effect.

Of course, many crucial pieces in this analysis are unavoidably difficult to pin down. The battlefield is foggy, especially from a distance, and much depends on the extent to which U.S. officials are able to identify responsible recipients. But the interim obligation suggests that caution may be a legal requirement, rather than simply good policy. By funding and carrying out arms shipments to the Syrian rebels, Congress and the President have implicitly concluded that those shipments are consistent with the United States’s interim obligations under the Arms Trade Treaty. For the treaty’s sake, it’s worth considering whether they are right.

Cross-posted on Ryan Scoville’s blog.