Senate races to watch - FT.com WISCONSIN - Tommy Thompson (R) vs Tammy Baldwin (D) This race to replace retiring Democratic senator Herb Kohl is known locally as "Tommy vs Tammy." Tommy Thompson, a four-term Wisconsin governor and former Bush administration health secretary who once ran for president, had until recently been expected to easily clinch the seat. But latest polls put Tammy Baldwin, one of the liberal members of Congress who would become the first openly gay senator if elected, in close range, if not ahead. This has surprised many analysts, but local Republicans still voice certitude that their candidate has the race in the bag. VIRGINIA - George Allen (R) vs Tim Kaine (D) Nowhere is the political art of "micro-targeting" more clearly on display than in Virginia, where Senate candidates are trying to get out every single vote. Former Republican senator George Allen is running again, accusing his Democratic opponent, former Virginia governor Tim Kaine, of supporting the bipartisan debt ceiling deal last year. The deal includes big cuts to the Pentagon's budget, which would have an outsized impact on the local economy. But Mr Allen is being noticeably restrained, after being accused of using a racist slur in 2006 and then losing by a narrow margin. Polls put Mr Kaine ahead. MONTANA - Denny Rehberg (R) vs Jon Tester (D) Democrat Jon Tester is facing the fight of his life to hold on to his seat in Big Sky Country, where he is facing a fierce challenge from Denny Rehberg, a sitting congressman. Mr Tester won by just one point in 2006 and Montana, which has long voted Republican for the presidential ticket, has tilted more to the right in the past six years, making re-election even tougher this year. Polls put Mr Rehberg ahead, and Nate Silver, the polling statistician who writes the Five Thirty Eight blog for the New York Times, gives him a 62 per cent chance of winning. NORTH DAKOTA - Rick Berg (R) vs Heidi Heitkamp (D) Democratic senator Kent Conrad, chairman of the Senate budget committee, decided to retire this year rather than face a difficult re-election. Republican congressman Rick Berg is now locked in a tight contest with former attorney-general Heidi Heitkamp. Although demographics suggest the seat should move into Republican hands, analysts say Ms Heitkamp, a centrist Democrat who is vowing to build another oil refinery in the state, is making a surprisingly strong run at the seat. Recent ads have even shown her in a batting cage swinging at a baseball (and connecting). MASSACHUSETTS - Scott Brown (R) vs Elizabeth Warren (D) The race between Republican incumbent Scott Brown and Democratic challenger Elizabeth Warren is exceptionally close. After months of trailing Mr Brown, Ms Warren has closed the gap and now has a narrow lead in the polls. She also has a huge financial advantage. She raised an astonishing $12.1m in the third quarter, much more than her rival's $7.45m haul. But Jennifer Duffy of the Cook Political Report still expects Mr Brown to win. "You have someone who is well liked, and you don't often see people like that lose, even in a Democratic state like Massachusetts," she said. NEVADA - Dean Heller (R) vs Shelly Berkley (D) Nevada offers a rare opportunity for Democrats to pick up a seat now occupied by a Republican. Dean Heller took over the seat in 2010 from the scandal-ridden John Ensign and is seeking re-election, but Democratic congresswoman Shelly Berkley has narrowed his lead in the polls and is now within striking range. The unions are strong in Nevada and the state has an increasing Hispanic population, benefiting Ms Berkley, but she is the subject of an ethics investigation that could damage her standing and is relatively unknown in the areas outside Las Vegas. Most analysts expect Mr Heller to eke out a win.