Religion as an issue runs up against the problem that there isn't in fact any issue. Obama's a Christian, like all previous Presidents have been, and a Protestant, like all his predecessors, apart form Kennedy. The suggestion that he's a covert Muslim is liable to run into the sand before long.

Much easier to make a big deal out of race - though harder in the actual election than in the primaries. It's easy enough to argue that a black candidate won't be able to get elected because of the existence of substantial numbers of racists in the electorate. And it's perfectly possible for someone to make that argument while protesting truthfully enough, no doubt, that they are in nio way racist themselves.

But once it comes to a general election that argument just doesn't work any more.