Andrew Romano in Newsweek asks a question about what he calls "the myth of the Obamacans," or Republicans who are going to cross over and vote for Obama in November. He marshals polls to point out that these people don't exist in large enough numbers to sway the election one way or another. But maybe he was asking the wrong question, or perhaps he was looking at the wrong groups.
Romano's question was this: "But are there enough rank-and-file Republicans whispering their support at Obama rallies to actually make a difference on Election Day?" The answer he gives to that question is an emphatic no, and for that question, he's probably right.
But Obama's not trying to bring over the rank-and-file Republicans. The rank-and-file Republicans are pretty much the only ones left who still like George W. Bush. Think I'm exaggerating? This poll puts people who identify as Republican, without leaners, at 28%. Bush's approval ratings haven't gotten out of the thirties for more than a year now. So no, Obama's not likely to pull from that pile.
Obama is more likely to pull from the pile that call themselves independent, but lean Republican, and even more so from the group identifies as independent, leans Democrat. Those groups are 11 and 15% respectively, with an 8% pile in the middle that swears it doesn't lean. Notice something about those numbers? Even if McCain gets all the rank-and-file and the leaners, he's at 39%. Give him the rest of the middle and he's at 47%. In short, it's more important that McCain pull from Obama's pile than vice versa.
One other factor--the Republicans have been losing people. Before the 2006 election, Republicans were 32% of the population. That number fell to as low as 24% before rebounding to the 28% in the one I mentioned above.
So what question should Romano have asked? Not whether the Obamacans exist, but where they're coming from, and I think the answer is that, based on the fact that Obama maintains a national and electoral college lead, they're not rank-and-file Republicans, but leaners who've moved over.