You can look at this and say that in three of the last ten presidential elections state polls have been off by more than Obama's current advantage--in which case Romney has a 15% chance. You can look at this and say that in one of the last five presidential elections in which there have been a lot of state polls have they been off by more than Obama's current advantage--in which case Romney has a 10% chance. You can say that 1992 was a special three-cornered race and that Romney has a less than 10% chance.
That is what being an actuary tells you about uncertainty at this point:
Nate Silver: https://www.evernote.com/shard/s1/sh/e5dd0baf-a7ac-47d7-b26e-aac12c622201/70103b7551039ffb5b87f502323af309
