One poll number I'm absolutely not worried about, or, why you shouldn't stress about Clinton supporters voting for McCain

In the frenetic back-and-forth between Barack Obama and Hillary Clinton, one oft-reported statistic is the number of each candidates voters who claim that they would vote for John McCain in the general election if their favored candidate does not win the Democratic nomination. This is often presented as bad news for the Democratic party. Here's a representative example of this kind of reporting:

A sizable proportion of Democrats would vote for John McCain next November if he is matched against the candidate they do not support for the Democratic nomination. This is particularly true for Hillary Clinton supporters, more than a quarter of whom currently say they would vote for McCain if Barack Obama is the Democratic nominee.

As would be expected, almost all Democratic voters who say they support Obama for their party's nomination also say they would vote for him in a general election matchup against McCain. But only 59% of Democratic voters who support Clinton say they would vote for Obama against McCain, while 28% say they would vote for the Republican McCain. This suggests that some Clinton supporters are so strongly opposed to Obama (or so loyal to Clinton) that they would go so far as to vote for the "other" party's candidate next November if Obama is the Democratic nominee.

Now, does this spell doom for the Democrats? On the surface, it could be ominous: if you take a random sample of 100 Democrats, and assume that roughly half support Obama and half support Clinton, then 28% of Clinton's supporters would turn out to be somewhere around 12-13 voters. Take those numbers to a state like Florida or Ohio, and they could be worrisome indeed.

However, I'm not at all concerned, for the following reason: this is an extraordinarily unusual primary process, with the race lasting far longer, and with far more bitterness, than you normally see, in either party. Because of this, the committed voters for each candidate have dug in to their positions, and find it hard to imagine that their candidate could lose the election. This makes sense: when you are supporting a candidate in the early days of the primary season, you likely have not supported him/her for that long, and consequently can easily transition to the candidate who gets the nomination.

Clinton and Obama supporters, however, have at this point been in their respective candidate's camp for an extended period of time. There is a good deal of hostility towards the opponent, who at this point is not John McCain. Given this, I'm not at all surprised that so many Clinton supporters claim they would support McCain. It makes sense that more Clinton supporters than Obama supporters claim they would support McCain--Obama, after all, is more likely to win the nomination, so to his supporters the idea of a choice between Hillary and McCain is an abstraction. For Clinton supporters, the eventual choice between Obama and McCain is very likely, and very likely hard to stomach.

Really, at this point those numbers are not a sign of Clinton's strength, but her weakness. The more her supporters come to grips with her likely withdrawl from the race, the higher the "I'll vote for McCain!" number will rise. It is, at this point, a tactic unto itself: they are trying to persuade superdelegates that voting for Obama will drive Democrats to McCain. Will it work? Probably not. Is it a credible threat? Perhaps, but not at the level suggested by those polls. I suspect that there is probably a hardcore element, say 5-6%, of Clinton supporters who will find themselves so disillusioned by an Obama nomination that they will chose to not vote. I doubt they'll support McCain, however.

I could be wrong about all this. But really, I think at this point the high number of Clinton supporters who claim they'll support McCain is more representative of their growing sense of the inevitability of her loss than anything else, and threatening to support McCain in the general is the only weapon at their disposal.