George W. Bush is the most unpopular president in modern US history. His disapproval rating now stands at 71 per cent – higher even than Richard Nixon’s, just before he was forced to quit over Watergate. With Mr Bush’s performance at home, and still-dwindling support for the war in Iraq, nobody need be surprised at this new record. What is surprising, however, and important, is that his toxicity shows no sign yet of infecting John McCain.

Mr Bush is unpopular; the Republican party is unpopular; but Mr McCain is doing pretty well. The Republican contender is a man of advancing years, given, let us say, to lapses of concentration, a forthright supporter of a failed war, and, it bears repeating, a Republican. Yet in some national polls he is tied with Barack Obama or Hillary Clinton, in others only a little behind. That a Republican not much loved even in his own party might win in November after eight years of Mr Bush seems scarcely credible, but it is a possibility the Democrats must take seriously.