Many of us anti-interveners now feel that we’re stuck on a hook; but, really, the situation has changed utterly since August 2013. Then, the Islamic State barely existed. Now, Syria’s options are so gruesome that many moderate states in the region find themselves backing militias affiliated with al-Qaeda — not out of any ideological affinity but because, between Assad and the Islamic State, they have become the least bad option.

The Islamic State has kidnapped and murdered U.S. and British citizens for no other reason than that they hold our passports. That, by almost any definition, is an act of war, inviting retaliation. Yet still we wriggle on with the anti-intervention barbs on which we impaled ourselves in 2013.

I am not suggesting an Iraq-style invasion. But there is now a strong case for targeted airstrikes, and for the establishment of safe areas, protected by international forces, rather as when the Kurdish part of Iraq broke away from Saddam. The mass of Syrians who support neither Assad nor the Islamist gunmen have never been given a chance. They were defeated, not at the ballot box, but on the battlefield.