Odd Polling

I'm kind of confused by why Obama's lead in the polls continues to grow. The race ought to be constricting as we close, rather than widening. Hell, in some polls I've even seen McCain losing ground.

Rather than any silly explanations that people might have (laying the credit at Colin Powell's feet, for example), let me suggest it's just the likely voter model changing. I've sort of suspected that pollsters have been dramatically understating how many of Obama's voters are actually going to vote. Now that early voting is happening the flaws in most polling models are beginning to show, as people they have as "not likely" have, in fact, already voted. As pollsters are forced to include the already voted in their polls, the demographics of the electorate change, and McCain loses a few points.