The past few months have been an uphill battle for the Democrats, who must gain six seats to make a Senate majority. After significant gains by the Democrats against GOP incumbents this fall, they are knocking on the Senate door.
But while only one Republican candidate has a strong chance at booting out a Democratic incumbent, Republicans have a guarded optimism that they will retain control — barely — as the votes come in today.
That said, anything could happen. So what are the races to watch when the polls start to close tonight? Here's our guide.
Keep in mind that Democrats last controlled the Senate in 2002. Republicans now control 55 seats in the 100-member chamber. Independent Rep. Bernie Sanders, who is expected to take the place of retiring Independent Jim Jeffords, and Sen. Joe Lieberman, running as an independent in Connecticut after losing in the Democratic primary, have pledged to join the Democratic caucus if elected and to vote with Democrats on organizational matters. If a 50-50 split is formed in the Senate, Vice President Dick Cheney serves as the tiebreaker, meaning the majority leader and committee chairs would be GOP, and any split-down-the-middle votes would be decided by Cheney.
Conventional wisdom says the Democrats are well-positioned to pick up seats in Ohio, Rhode Island and Pennsylvania. They are leaning behind in Tennessee, which was a toss-up a week ago. If they lose there and hold all their current seats, Democrats would then need to win all three remaining toss-ups: Virginia, Missouri and Montana.
At 7 p.m.
Ending a race of big personalities and bare-knuckles campaigning, Virginia polls close. Jim Webb is a best-selling author, Vietnam Marine and former Republican. Once a long shot, he has made the race a toss-up. Sen. George Allen was a presidential contender a year ago, but now he's fighting for his life after a series of campaign gaffes and errors. A win for Webb may be crucial for Democratic hopes.
At 7:30 p.m.
Ohio polls close. Sen. Mike DeWine is trailing his Democratic challenger, seven-term Rep. Sherrod Brown, in recent polls. Is Ohio, the state that put President Bush over the top in 2004, trending blue? The last time a Democrat won an Ohio Senate race was 1992, making this a possible upset to watch. The Democrats are counting on a win here.
At 8 p.m.
At 9 p.m.
Polls close in Rhode Island, where Republican Sen. Lincoln Chafee, who had been written off by some observers, has narrowed the gap with Democratic challenger Sheldon Whitehouse to 3 points in the latest USA Today/Gallup poll. A Mason-Dixon poll showed Chafee within one percentage point of Whitehouse.
At 10 p.m.
The last of the big races close their voting booths. In Montana, where Republican Sen. Conrad Burns had been struggling, polls are inconclusive, either showing Burns and Democrat Jim Tester tied (Mason-Dixon), or Tester with a 9-point lead (USA Today/Gallup). Monday, a Burns spokesman dismissed the USA Today/Gallup poll as inaccurate and said the campaign was revoking one newspaper's credentials to attend Burns' election night event in Billings because it wrote about the poll.
Undoubtedly, the night will have some surprises. Arizona Republican Sen. Jon Kyl could be in for an unexpectedly close race, some observers say. So could Democratic Sen. Debbie Stabenow from Michigan.
It could be a long night, and polls in California and Hawaii don't close until 11 p.m. It will certainly be an important night in American politics.
By Christine Lagorio