In the early days of the Trump administration, President Trump focused his Syria strategy on the fight with ISIS. As I noted elsewhere, despite ever-mounting civilian casualties, President Trump seemed content to leave President Assad in place. When Syria used sarin gas—a particularly toxic chemical weapon—on its own civilians, however, President Trump claimed that the attack changed his “attitude toward Syria and Assad very much.” He condemned the attack, and, after US-led efforts for UN action failed, President Trump authorized a missile strike on the Syrian air base that launched the chemical attacks. I wondered at the time whether this strike would be used as precedent for future military enforcement of weapons treaties.
Almost a year after the strike on Syria, the Trump administration’s resolve to enforce the Chemical Weapon Convention with force is being called into question. In late January 2018, first responders accused the Syrian government of using chlorine gas in a rebel stronghold Eastern Ghouta.. The UN is currently investigating reports of their use there as well as in the Idlib area. If true, this use of chlorine gas would violate Syria’s 2013 pledge to dismantle its chemical weapons and join the Chemical Weapons Convention—a pledge notably offered in exchange for then-President Obama’s promise not to conduct a military strike on the country.
The administration has signaled some willingness to strike again. After the late January reports reached the United States, the State Department indicated it was “gravely alarmed” by the allegation of chemical attacks, criticized Russia for blocking a UN Security Council declaration condemning the alleged attack, and “implore[d] the international community to speak with one voice, taking every opportunity to publicly pressure the Assad regime, and its supporters, to cease its use of chemical weapons.” US Ambassador to the United Nations Nikki Haley went so far as to suggest that the evidence of chemical attacks was conclusive, commenting, “We have reports that the [Bashar al-]Assad regime has used chlorine gas against its people multiple times in recent weeks, including just yesterday. . . . There is obvious evidence from dozens of victims.” A few days later, Secretary of Defense James Mattis seemed to escalate the message, warning Syrian President Bashar al-Assad that he would be “ill advised” to launch new chemical weapons attacks, adding, “(w)e’re on the record and you all have seen how we reacted to [your 2017 violations].” Similarly, Secretary of State Rex Tillerson has indicated that military action is on the table, noting that “[a]s it was in April last year, we are serious about our demands that chemical weapons not become regularized or normalized as a weapon in any conflict.” Most recently, this weekend National Security Advisor H.R. McMaster confirmed at an international security conference that “Public accounts and photos clearly show that Assad’s chemical weapons use is continuing.”
France now also supports the use of military force to respond to chemical weapon use. In May 2017, France declared the use of chemical weapons as a “red line” where “(a)ny use of chemical weapons would result in reprisals and an immediate riposte, at least where France is concerned.” On February 9, French President Macron raised serious concerns on a phone call with Russian President Vladimir Putin that chlorine weapons had been used against civilians in Syria. He then publicly emphasized, “(o)n chemical weapons, I set a red line and I reaffirm that red line” and declared that France would strike if chemical weapons had been used against civilians in violation of international treaties.
But will the US or France really strike Syria? Syria has categorically denied possessing chemical weapons and reiterated that the government “consider(s) the use of such arms as immoral and unacceptable, whatever the context.” Russia seems likely to block any security council efforts to respond to Syria, leaving states faced with the decision of whether to pursue force without the legal and moral imprimatur of the United Nations. The United States and France have used some hedging language that would allow them to walk back from their commitments.
Level of Proof
First, France has suggested it needs to make its own determination that Syria used chlorine gas and that such use was lethal. France maintains that “our agencies, our armed forces, have not established that chemical weapons, as set out in treaties, have been used against the civilian population,” though Macron affirmed that “[a]s soon as such proof is established, I will do what I said.” If France wants to avoid strikes, Macron might demand stronger evidence of proof than when the US relied on OPCW (Organization for the Prohibition of Chemical Weapons) reports to justify its 2017 strike on Syria. The OPCW investigations included a fact-finding mission; open source information; requests to member states, including Syria, for information; witness interviews; review of photographs, videos, documents and other materials; analysis and expert assessments from forensic institutes; satellite imagery; and expert analysis on medical effects, munitions and their delivery methods. It is unclear whether France would be satisfied with a similar OPCW report here.
Distinction Between Sarin and Chlorine
The United States might also be hedging or at least walking back the red line a bit. The United States might try to draw a distinction between sarin and chlorine weapons. For instance, even as Mattis acknowledged that the Syrian government has repeatedly used chlorine as a weapon in the past, he emphasized his greater concern about sarin use, despite both being prohibited under the Chemical Weapons Convention. Some fear that “chlorine gas attacks in Syria have become normalized, allowing President Bashar al-Assad to deploy them with impunity.”
Such normalization would be deeply problematic. While chlorine has many important, legitimate uses, chlorine gas is deadly and for those it doesn’t kill, it can lead to severe pain, blindness, and chronic respiratory dysfunction. Chlorine gas is probably best known for its use in World War I when the German army buried thousands of canisters near Ypres. After the gas’s release, over 800 soldiers died and over 2000 more were incapacitated. It presents a serious domestic and foreign threat as terrorists could target the industrial production or transportation of chlorine thus deploying a chemical weapon “without having to manufacture or transport it themselves.” Intentional releases in highly populated areas could risk hundreds of thousands of injuries. And even smaller scale use is a clear violation of the Chemical Weapons Convention that ought to be strongly condemned.
But whether use should be condemned through a military strike isn’t only a policy question; it is also a legal one. Under traditional understandings, states may not engage in the use of force under the UN Charter unless they have a case for self-defense or a UN authorization. Some have argued that states additionally ought to be able to use force for humanitarian interventions, even in the absence of textual permission under the UN Charter. But to whatever extent the legality of humanitarian interventions has been accepted, the legality of strikes to enforce weapons treaties is much less clear. No legal rationale has yet been offered by either the United States or France to justify a future strike.
So what rationales were offered last time? President Trump and his administration provided several short policy justifications for the strike, but never a legal one. Trump stated the night of the attack that preventing and deterring chemical weapons was in the “vital national security interest” and that the region’s continued destabilization “threat[ened] the U.S. and its allies.” Secretary of State Rex Tillerson expanded on this position, suggesting that Syrians might bring these chemical weapons “to our shore [which] is a direct threat to the American people.” Yet, multiple administration statements also suggest the strike was deeply humanitarian in nature, responding to, and attempting to prevent future, Syrian civilian casualties. For instance, National Security Advisor H.R. McMaster stated that the attack was motivated by the “risk of this continued, egregious inhumane attacks on innocent civilians with chemical weapons.” Yet none of these statements explained why the attack was either consistent with (1) existing international law governing the use of force or (2) part of a new strategy to broaden legal authority for force in service of humanitarian interventions or (3) a new lawful mechanism for the enforcement of chemical and other weapons treaties. I don’t expect the administration to give a detailed legal explanation this time either, but doing so could provide some much needed clarity and guidance to the international community.