Josh Rogin reports that John McCain wants to start another illegal war:

“What opposition groups in Syria need most urgently is relief from Assad’s tank and artillery sieges in many cities that are still contested. Homs is lost for now, but Idlib, and Hama, and Qusayr, and Deraa, and other cities in Syria could still be saved,” McCain will say. “But time is running out. Assad’s forces are on the march. Providing military assistance to the Free Syrian Army and other opposition groups is necessary, but at this late hour, that alone will not be sufficient to stop the slaughter and save innocent lives. The only realistic way to do so is with foreign airpower.”

It didn’t take McCain very long to go from urging arms for Syrian rebels to demanding U.S. military action. That’s how it usually works. Interventionists propose a minimal, limited measure, and skeptics point out that it isn’t going to achieve anything. The interventionists then inevitably propose to escalate our involvement even more. The first proposal is meant to force people to start debating military options, which opens the door for more aggressive measures.

One of the many problems with McCain’s proposal is that it is not a very realistic option:

However, this type of air campaign would be far more complex and difficult than advocates acknowledge, because tactical air strikes would first require establishing an NFZ and neutralizing air defense capabilities through larger strikes. Regime forces and the opposition are primarily clashing in densely packed urban areas. In contrast to Libya, there are no front lines to police, few tank convoys to destroy on desert highways and no offensives by rebel armies for which an air campaign would clear a path. Civilian casualties would inevitably result from a bombing campaign against ill-defined targets in urban areas with extremely limited human intelligence.

In addition to the difficulties of waging an air war against Syria, there is the small matter that the U.S. and any allied governments would have absolutely no legal sanction for such an action. I know this doesn’t matter to McCain, but it is not sustainable to keep posing as enforcers of a “rules-based international order” if our government consistently bends and breaks those rules when it is convenient. Because of the lack of U.N. authorization, there would be almost no support coming from European governments for U.S. military action. The U.S. would be attacking Syria with little or no political cover from any other states. There is no way of knowing whether an air war against Syria would trigger a larger regional war, but the fact that hawks aren’t even considering this should be enough warning that starting a Syrian war is an unacceptable threat to regional stability.