Barack Obama remains popular with US voters. His approval rating has slipped only a little, and stands at roughly 60 per cent. But independent voters – the key to Mr Obama’s success – seem to have growing doubts. And poll after poll shows that the president’s policies are less liked than he is.

One can exaggerate his difficulties. Today US voters are divided 50-50 between those who think the country is moving in the right direction and those who think not, a slight worsening since the previous reading. Last November the proportion thinking the country was on the right track was in single figures. Mr Obama’s support is slipping, but from a high level.