According to the last pre-election poll from PPP, Colorado, Pennsylvania, and New Hampshire — all states President Obama carried in 2008 — are drifting away:

2010 voters in Colorado, New Hampshire, and Pennsylvania all say they’d prefer a generic Republican to Obama in 2012. In Colorado it’s a close 45/50 spread, in New Hampshire it’s 40/54, and in Pennsylvania it’s 42/52. Those troublesome numbers for the President speak to two things. First, he obviously needs to get his supporters who dropped off in 2010 back to the polls in 2012…in all three of these states the electorate this year was a good deal more Republican than in 2008. Second and perhaps more worrisome for Obama though it speaks to the reality that he has picked up virtually no support since taking office, while he has lost a decent amount of it.
In Pennsylvania 11% of 2008 Obama voters say they’re inclined to vote Republican next time while only 2% who voted for McCain say they would now vote for Obama. Similarly in New Hampshire 11% of Obama voters are leaning toward supporting a GOP candidate next time to just 4% of McCain voters he’s converted to his side. And in Colorado it’s 12% who supported Obama the first time around who are now looking more toward the Republicans and only 5% of McCain voters who say Obama’s won them over.
Based on last week’s results the state out of this group that might be most worrisome for Obama is New Hampshire, where his numbers have fallen precipitously and the Republican Senate candidate won by greater than 20 points. Even though Obama’s numbers in Colorado don’t look good voters there sent a strong message looking toward 2012 that they’re willing to vote for a Democrat they’re not enamored with if the Republican alternative goes too far to the right. It seems safe to say Sarah Palin would not defeat Obama in Colorado. Pennsylvania falls in between New Hampshire and Colorado in how big of a concern it should be for Obama moving forward…it did end up going Republican but by a relatively tight margin given how bad this political climate is for Democrats.

More here. The same poll shows Mitt Romney with a big lead among likely Republican 2012 contenders in New Hampshire, and a narrower lead in Colorado. Pennsylvania, by contrast, tilts for Mike Huckabee. More on the Republican stuff here.