Like a corpse that sits bolt upright when electrocuted, US neoconservatives keep springing back to life. The electric charge comes at regular intervals – Syria’s use of chemical weapons, Russia’s annexation of Crimea, China’s growing maritime assertiveness, and now the return of Sunni extremism in Iraq. Their rehabilitation is abetted by the television networks: whenever there is a global setback, the same old faces run for the cameras and claim it is 1939. That is what they do. And the media loves them for it.

But there is something more credible about their current revival. Maybe that twitch is a 2016 presidential hopeful wondering whether there might, after all, be something to the doctrine they espouse. Churchill’s definition of a fanatic is someone who can’t change their mind and won’t change the subject. Every now and then the subject turns their way. Today’s world, with all its seeming chaos, offers neoconservatives their best conversational opening since September 11 2001.

There are three things behind their growing self-confidence. First, the US public has stopped listening to Barack Obama, their supposed nemesis. Mr Obama’s declining popularity derives largely from his inability to get things done at home. On the face of it, US public opinion supports his foreign policy goals. Overseas entanglements are unpopular. American boots on foreign ground are deeply unpopular. Mr Obama has been catering to the public on both counts. By the end of next year there will be no US troops in either Afghanistan or Iraq.