US embassies stormed, American flags burnt, diplomats assassinated. These images have played on our television screens over the past week, giving the impression of a region in deep turmoil, its rage targeted violently at the US.

Predictably, the unrest has damaged Barack Obama, the American president who has made outreach to the Muslim world a cornerstone of his foreign policy. Worse, the fury exploded in the midst of a heated presidential campaign, giving Mr Obama’s opponents fresh ammunition to portray him as a weak leader. The president had already been under fire for supposedly being too soft on Islamists rising to power in north Africa and not tough enough on Iran and its dogged pursuit of a nuclear programme.