The United States, Britain, and France have attacked various chemical weapons facilities in Syria. Even before they acted, a number of commentators claimed that any such attack would be internationally unlawful. Below, I explain why that claim is too simplistic and how we should situate the operation in the jus ad bellum going forward. Let me say at the outset that I don’t support this operation and have serious doubts about the capacity of the United States, in particular, to implement a coherent policy in Syria. (I also think the operation violates U.S. law.) So, I’m not arguing that the operation was a good idea or even that it should be lawful. I’m making an analytic argument about how the jus ad bellum works.
The April 2017 Incident
This was not the first attack against Syria for its use of chemical weapons. In April 2017, the United States struck Syria for the same asserted reason: as a reprisal for the regime’s use of chemical weapons in violation of international law. At the time, most commentators said that the U.S. operation was unlawful. It was inconsistent with the longstanding interpretation of Article 2(4) of the UN Charter and not covered by the Charter exceptions. Assad didn’t consent to the operation, the Security Council hadn’t authorized it, and it wasn’t taken in self-defense.
There is an ongoing debate about whether the jus ad bellum contains another exception for humanitarian interventions. The dominant view is that it does not. States (as a group) have periodically condoned unilateral operations that can be labeled “humanitarian,” but the vast majority of them have declined to support a generally applicable humanitarian exception to 2(4). They have instead insisted that no such exception exists. Further, even if there were one, its application to the 2017 operation would have been dubious. The operation looked more like a reprisal than like what we usually mean by a “humanitarian intervention.” President Trump said that it was designed “to prevent and deter the spread and use of deadly chemical weapons,” not to avert the many other atrocities that were being committed in Syria. Forcible reprisals are by almost all accounts unlawful. Read the rest of this entry…