There's More Than One Effect

We shouldn't discount the "Bradley Effect" and its role in the upcoming election. It's indeed possible that the polls are artificially inflated by people claiming they'll vote for Obama when polled, but not being able to bring themselves to throw down with a black man once they're in the voting booth. I'm willing to bet this will factor into the final count.

However, it's useful to also consider the Republican side of the equation. Per Five Thirty Eight, the Elephant Effect.

So, it wasn't just black Republicans who were undeperforming their polls; it was white Republicans too (likewise with Rick Santorum in Pennsylvania): not a 'Bradley Effect' so much as an 'Elephant Effect'.

Nate Silver is playing a little too much "inside baseball" for my taste here, but the takeaway is that plenty of "Nobama" people hate McCain as much, or almost as much, as the Democrat here. They will say they want a pro-choice guy who suspended his campaign to ensure the bailout went through, to pollsters; but on election day they may leave the box unchecked, or write in Mitt "Mittens" Romney instead. So most likely these two "effects" will cancel each other out.

The reason to mistrust polls is this: they're polls, goddammit!