A different challenge for Mr Obama, widely discussed, if mostly sotto voce, is the race problem. It’s almost universally believed in Democrat and liberal circles that large numbers of Americans are simply too racist to vote for a black man and that this fact will place a low ceiling on Senator Obama’s potential vote.

It is impossible to know how much of a problem his race is. But it might at least be useful to distinguish between straight bigotry — an ugly disposition that will certainly move some voters — and a different and surely more legitimate attitude; that is, a lack of susceptibility among others to the Senator’s “transcendent” appeal beyond usual class and economic barriers. Senator Obama has based his campaign on this appeal, but you don’t have to be racist to believe that, at a time of economic distress and concern about America’s role in the world, the laudable aim of raising the American people’s eyes to loftier ideals may not be seen as an immediate priority for some voters.

In fact, for all the talk of change in the primary campaign, it was the Democrats who seemed unhealthily obsessed with issues of race and class. Although it was undeniably competitive, the contest between Senators Clinton and Obama came down in the end not to a debate about the type and direction of change the country needed, but to a struggle between two large competing demographic blocs — Senator Obama’s blacks, the well-educated and young voters, and Senator Clinton’s whites, blue-collar and older voters.

For much of the time, it seemed oddly free of discussion of the issues that concern most voters and focused much more on the modern dark political arts of low-information political signalling and dog-whistle politics. That should give Senator McCain an opportunity to make his case, especially in an area that has proved pivotal in recent elections — national security.