Anyone wondering about the scale of the anti-Obama backlash should look at its impact on the 2016 US presidential race. Both major parties are looking for candidates with genuine executive experience. The Republican list of hopefuls is filling up with sitting governors. Among Democrats, hopes rest mainly with Hillary Clinton. Should Elizabeth Warren, the popular senator from Massachusetts, enter the fray Mrs Clinton’s riposte would trip off the tongue. Ms Warren has no governing experience, she could say. And we all know the risks of that.

Having authored an inspirational politics, President Barack Obama’s difficulties are spawning a new fashion for perspiration. Given its limited powers, the strength of the US presidency derives largely from its occupant’s credibility.

Faith in Mr Obama’s competence was already negative. Doubts now extend to his personal integrity. A majority of Americans tell pollsters that they no longer believe he is always telling the truth. Were Mr Obama in a different system, he would be fending off a leadership challenge or facing a snap election. Since the US constitution rules out those options, Mr Obama is in danger of becoming a permanent lame duck.