"Could Al-Qaeda come back? Yeah. But what's the strategy? Every place where Al-Qaeda is, we're going to invade and have troops stay in? C'mon!". That was US President Joe Biden's latest and very tetchy response when questioned about his strategy to fight terrorism.

It's not difficult to understand why Mr Biden is angry. He has been on the receiving end of a torrent of criticism from both political foes and traditional allies who not only brand his decision to pull out of Afghanistan a catastrophic mistake, but also question his broader ability to govern. "C'mon" is a favourite Biden expression, used whenever he wants to suggest that his critics are not merely wrong, but perhaps also deluded.