Bad news for Senate Republicans

The four seats most likely to change parties in 2010 are currently held by Republicans, according to Nate Silver:

1. New Hampshire (R-Open)
The Granite State vaults to the top of the list with Judd Gregg's move to Commerce. Gregg was a valuable player for the GOP: not only was he a Republican in what has increasingly become a Democratic state, but he was afairly conservative Republican who was nevertheless fairly popular in a Democratic state. Gregg's designated successor, Bonnie Newman, is supposedly not going to run for re-election, and even if she does, she is not likely to be nearly as formidable an opponent as Gregg was. In an open seat race, Democrats are the favorites, especially with Paul Hodes already having declared his candidacy.

2. Missouri (R-Open)
Kit Bond has announced his retirement since our last edition, and meanwhile, Democratic Secretary of State Robin Carnahan has stepped into the void and announced her candidacy. That's good news for Democrats as Carnahan has polled as a slight favorite against several potential Republican opponents. It's possible that Carnahan will lose ground if the political tectonics shift back toward the Republicans -- Missouri is one of those states that could be vulnerable to a populist Republican revolt. But this race is at least a toss-up, and probably leans Democratic if Republicans have trouble picking their opponent while the field clears for Carnahan.

3. Ohio (R-Open)
Yet another Republican seat that has opened up since last month's rankings. The difference here is that the Republicans have a seemingly strong candidate in former Congressman and Bush cabinet official Rob Portman. Quinnipiac, however, has Portman trailing trailing a couple of prospective Democratic opponents. The good news for Republicans is that Portman has surprisingly low name recognition statewide, something he'll have no trouble fixing as he should raise plenty enough money to do some early advertising.

4. Kentucky (R-Bunning)
Republicans are trying their darndeset to get Bunning to retire rather than run for re-election, but it doesn't seem to be working, and meanwhile Research 2000 shows several potential Democratic opponents polling within the margin of error against him. One caution for the Democrats: I'm not sure that Daniel Mongiardo, the Democrat who nearly upended Bunning in 2004 and who has announced his interest in the seat, is necessarily the strongest opponent, as his negatives are fairly high statewide. Still, Bunning is not a good campaigner at this stage of his career, and if he's getting little institutional support from John Cornyn and the GOP leadership, he could be in a lot of trouble.

He ranks the remaining 33 races as well.