U.S. officials have said that the U.S.-led coalition in Syria struck pro-Assad forces that were advancing inside an established “de-confliction” zone and toward a military base that the coalition was using to train anti-ISIS fighters. As Jen Daskal noted, the strike was not intended to reflect a change in U.S. policy; U.S. officials claim that they acted to protect U.S. and partner forces in the field. The incident raises pressing questions about two issues: the scope of Congress’s 2001 Authorization to Use Military Force (AUMF) and the risk of escalation.

As many readers no doubt know, the executive branch justifies its military campaign against ISIS under the 2001 AUMF, on the notion that ISIS is a successor to al-Qaida. The executive has never claimed that the AUMF also authorizes the use of force against a foreign state other than Afghanistan. When the United States attacked Syria in response to its use of chemical weapons in April, the Trump administration justified the operation under the President’s Article II Commander-in-Chief authority. The administration presumably did so because, absent strong evidence of something amounting to co-belligerency with ISIS or al-Qaida against the United States, the AUMF could not plausibly be interpreted to cover a military campaign against Syria or any other state that operates there.

The recent strike in Syria presents a new wrinkle: if the AUMF authorizes the fight against ISIS, then extending it to operations that are designed to protect ISIS-fighting forces does not seem like such a stretch. In other words, the administration might invoke the AUMF to justify operations against Syria, if such operations are necessary to protect our forces in the field. That potential application of the AUMF betrays just how far down the slippery slope we have fallen. (Indeed, some news outlets and reporters have written that the strike might have hit Syrian regime forces or forces that are backed by Iran.) What’s more, because the geopolitics in Syria create an acute risk of escalation—not only directly with Syria but also with Russia and Iran—it’s important to get more information about exactly what happened: why did the incident occur, have similar incidents occurred before, does the administration anticipate further confrontations with pro-Assad forces, and what is it doing to reduce that possibility?


Photo: A U.S. Marine Corps AV-8B Harrier during a mission in support of Combined Joint Task Force Operation Inherent Resolve over Iraq, Feb. 22, 2017.The KC-10 Extender offloaded 126,000 pounds of fuel to multinational coalition aircraft working to weaken and destroy Islamic State in Iraq and Syria operations. Air Force photo by Senior Airman Tyler Woodward