This past Thursday, in a reversal of President Donald Trump’s decision to withdraw all U.S. military forces from Syria, the White House announced that “a small peacekeeping group of about 200 will remain in Syria for a period of time.” Senator Lindsay Graham lauded the creation of a so-called “safe zone in Syria,” purportedly made up of “international forces,” which he described as “the best way to achieve our national security objectives.” On the top of Graham’s list of objectives was “continuing to contain Iran.” Meanwhile, the New York Times reports a “senior official” revealed that in fact, U.S. troops will “not be peacekeepers,” and that a few hundred more U.S. troops will remain at the al-Tanf outpost in southeast Syria to continue training “local Syrian fighters” and to “monitor Iranian-backed militias in the area.”

The chaos around the U.S. military presence in Syria seems to reflect a badly broken policy process. White House announcements raise more questions than they answer, including for those working on Syria within the U.S. government who, following Thursday’s announcement, “described a surreal atmosphere” and “no longer know what to expect from one day to the next.” Will there be a “multinational force” engaged in a “peacekeeping” mission? Who is supposed to be kept “safe” from whom and in what “zone”? What international partners will be involved? And would any of this be legal?

Uncertainty around that last question – the legality of a continuing military mission in Syria – may be related to difficulty finding willing partners. As U.S. officials reportedly attempt to get European allies, like the UK and France, to put boots on the ground in Syria, one of the threshold questions they’ll need to answer early in any policy process within their own governments is whether it would be lawful to take such action.

The Times reports that a “senior official” made clear U.S. troops “would not operate under a United Nations peacekeeping mandate.” Given there is currently no UN Security Council authorization for such a mission and key U.S. officials like National Security Advisor John Bolton are openly hostile to a UN mandate in any event, this isn’t much of a revelation (there’s also no reason to believe long-term Russian hostility to a UN force authorization would change now). But it begs the question – under what kind of mandate would a multilateral force operate?

Currently, the U.S. and its few coalition partners operating in Syria don’t have a mandate from anyone – they lack UN Security Council authorization and they also do not have the consent of the Syrian government to use force within its territory. Instead, their argument is that Syria is “unable or unwilling” to effectively address the threat posed by ISIL (and for the U.S., also al-Qaeda), and thus it is “necessary” in self-defense against ISIL to use force within Syrian territory. The Obama administration took this position in 2014, and the Trump administration’s reporting to Congress has maintained this approach. Under this interpretation of international law, a state may use force in another state’s territory in reliance on the “unable or unwilling” standard “if measures short of force have been exhausted or are inadequate to address the threat posed by the non-State actor [ISIL] emanating from the territory of another State.” As I’ve noted previously, the “scope and content of this self-defense theory, and even its existence as a rule of customary international law, remain deeply contested.”

It was no simple task to get coalition partners to go along with this controversial interpretation of international law in the thick of the counter-ISIL campaign – indeed, many did not, choosing instead to operate only on the Iraqi side of the border with the consent of the Iraqi government. It’s even harder to see how an “unable or unwilling” basis for using force in Syria would extend to all of the types of missions hinted at in the White House’s identification of “peacekeeping” and the descriptions by “senior officials” and Senators close to the President of what that might entail.

First, going on the offense against Iran in Syria is certainly not part of a valid invocation of self-defense against ISIL. It’s worth noting that for the United States, as former State Department Legal Adviser Brian Egan and I explained previously at Just Security, it also isn’t legal under domestic law. Nevertheless, as currently reported, this appears to be a key component of the mission for any U.S. forces that would remain at the al-Tanf outpost, if not elsewhere in Syria.

Second, discussion of a “safe zone” doesn’t seem to refer to multinational forces setting up a heavily-defended area in which civilians will be protected from violence by all parties – as that term may conjure – but rather refers to the goal of keeping Turkish forces and Kurdish armed groups operating within Syria separated to prevent further outbreaks of violence between them. That goal is a worthy one, but it is far removed from countering ISIL (or al-Qaeda). The Trump administration has argued that even shooting down Syrian jets is a component of its exercise of self-defense against ISIL, on the grounds that Syrian forces or their allies sought to interfere with the counter-ISIL campaign and thus it was “necessary” in the exercise of self-defense against ISIL to use force against Syrian and allied forces. It would be quite a stretch, though, to argue that establishing a buffer force between Turkish and Kurdish forces is a necessary exercise of self-defense in the counter-ISIL campaign, particularly after ISIL has been pushed out of the area.

The goal of preventing ISIL from regrouping presents a harder case, and one that merits more extended analysis. Arguably, with ISIL’s near total loss of territorial control, it’s now difficult to maintain that it remains truly necessary (rather than discretionary) to use force within Syrian territory. But regardless of where a government draws that line, muddying the waters with talk of countering Iran and other non-ISIL related goals will make it harder to explain to potential partners that an ongoing U.S. military mission in Syria will truly be a counter-ISIL one alone, if at all. And addressing the threat posed by ISIL remains the only military goal in Syria that some of our most important international partners believe to be permitted under international law (unless the UK believes humanitarian intervention would justify using force to achieve any of the goals discussed here, which seems unlikely).

Finally, let’s not forget that the chaos of the current policy process in Washington makes diplomacy aimed at coalition-building extremely difficult. No doubt, some actors involved in that policy process truly do want to see the United States remain committed to a long-term counter-ISIL mission, with a secondary goal of supporting the Kurdish armed groups that did the lion’s share of the fighting on the ground in the counter-ISIL campaign. Others, particularly in the White House, may have their sights set on staying in Syria to go after Iran. U.S. officials engaged in talks with foreign governments are likely speaking about the former at the negotiating table. But any prospective U.S. partner may question whether they are being asked to sign up for the latter.

Photo credit: Louai Beshara/AFP/Getty Images