Democrats currently hold 51 Senate seats to the GOP's 47, with two Independent senators voting with the Democrats. Here's a quick rundown on the various close Senate races across the country. Polls don't start closing until the evening on Tuesday, but news, gossip and exit polls will start to surface in the hours ahead. This article will be updated regularly.
1. Indiana Senate : Republican state Treasurer Richard Mourdock (R) vs. Rep. Joe Donnelly (D). The most recent serious poll in Indiana shows that Donnelly has jumped ahead of Mourdock by 3 points, 45-42. Pundits are saying that if the GOP can't win this seat, GOP chances of taking the Senate are somewhere between slim and none.
2. Nevada Senate : Appointed Sen. Dean Heller (R) vs. Rep. Shelley Berkley (D). Heller is leading between 2-6 percent in recent polls. Berkley is the subject of an ethics investigation, while Heller as an appointed senator enjoys name recognition. But Obama's huge ground game in Ren0 and Las Vegas could very well scratch that lead and deliver Nevada to the Dems.
3. Montana Senate: Sen. Jon Tester (D) and Rep. Denny Rehberg (R). Both candidates have seen leads in recent polls from October, and this race figures to be a squeaker .
4. Virginia Senate: Former Democratic National Committee Chairman Tim Kaine (D) has led in the past four major polls in Virginia, against former Sen. George Allen (R) by 2-6 percent .
5. Massachusetts Senate: Elizabeth Warren (D) has pulled ahead of incumbent Scott Brown (R) in the vast majority of polls in recent weeks by as much as 7 percent.
6. North Dakota Senate: Republican Rick Berg has led by a margin as high as 10 points against Heidi Heitkamp this October, but the most recent poll has him leading by only 2 points.
7. Wisconsin Senate: Former Gov. Tommy Thompson (R) vs. Rep. Tammy Baldwin (D). Baldwin has been ahead by a margin of approximately 3 percent in the recent polling. Baldwin, if elected, would be the first openly gay woman to be elected to the U.S. Senate.
8. Missouri Senate: Sen. Claire McCaskill (D) leads Rep. Todd Akin by an average of 6 percent in recent polling, as Akin's comments that “legitimate rape” rarely cause pregnancy continue to dog him.
9. Ohio Senate: Sen. Sherrod Brown (D), one of the best progressive advocates in the Senate, has been leading his opponent Josh Mandel in every poll released to the public by 1-11 points since Oct. 4.
10. New Mexico Senate: Former congresswoman Heather Wilson (R) was supposed to be a strong candidate, but she has trailed Rep. Martin Heinrich (D) in all the polls this October by as much as 10 percent.