Almost all of the published polls show Obama getting less than 50% of the vote and less than 50% job approval. A majority of the voters either support Romney or are undecided in almost every poll. But the fact is that the undecided vote always goes against the incumbent… an undecided voter has really decided not to back the incumbent. He just won’t focus on the race until later in the game. So, when the published poll shows Obama ahead by, say, 48-45, he’s really probably losing by 52-48!
Relying on the work of Nate Silver, Dave Weigel notes that there is "literally no evidence that undecided voters will break the way [Morris] says they're breaking." Drew Linzer further unspins the GOP's new spin:
If the polls are all biased 2% in Obama’s favor, the simulation moves Romney up to a 37% chance of winning – still not great, but at least better than 8%. No wonder the Republicans are starting to challenge the polls. Unfortunately, there’s no serious indication that the polls are behaving strangely this year.