Right now the Democrats control 53 seats and the GOP holds the other 47. 33 will be up in the next election. Here's how they look.
Solid GOP: (8)
GOP Pickups: (4)
Leaning GOP Pickups: (2)
Toss ups: (3)
-Ohio-I know Sherrod Brown was polling well ahead of Josh Mandel but that will soon change. Brown is the most liberal member of the Upper House and Mandel will make that known in a state that's slightly red.
-North Dakota-I would have assumed the GOP would take this seat but the former Democratic Attorney General of the state has jumped in and she's formidable.
Lean Dem: (9)
-Minnesota-If the Democratic incumbent doesn't get a strong challenger she'll run away with it.
-Hawaii-This could prove a big surprise. The former GOP governor is mounting a tough challenge.
-California-Diane Feinstein is tough but she's out of campaign money and she hasn't yet announced.
-Pennsylvania-The GOP has yet to put up a tough challenger against Bob Casey. He's beatable if a good Republican runs.
-New York-The GOP has put a solid Republican in the race against Kirsten Gillibrand but she'll be tough to unseat in this solidly blue state.
Solid Dem: (5)
Possible Dem Pickups: (2)
Right now the GOP is poised to pick up at least six seats. If they lose Massachusetts and Nevada they'll still have a majority (51) but it will be slim. At the same time, if they did get several breaks, they could gain as many as sixteen (certainly unlikely) but if they got thirteen they would have a filibuster-proof majority. In 1980 the GOP picked up twelve Senate seats, including several thought to be out of reach. It is reasonable to assume that the Democrats will take significant losses in the Senate (and the GOP should easily keep the House) even if the President wins reelection. This could very well prove to be the fourth "wave" election in a row. Most of the faces in the House and Senate in the last ten years are new. If the President does win reelection, the Senate class of 2014 will be particularly vulnerable and the GOP will probably end up with more than sixty seats after that cycle.