A look at the most closely watched of the 33 Senate races:
Arizona: Sen. Jon Kyl is seeking a third term, challenged by businessman and former party chairman Jim Pederson, in a race Democrats hope to make competitive.
Connecticut: Anti-war challenger Ned Lamont defeated Democratic Sen. Joe Lieberman in last month’s Democratic primary. Now the incumbent is back, running as an independent. Republicans show no interest in their own candidate, Alan Schlesinger.
Maryland: Racial politics make for unpredictability. Republican Lt. Gov. Michael Steele, who is black, will face the winner of a Sept. 12 Democratic primary showdown between Rep. Ben Cardin and Kweisi Mfume, former head of the NAACP.
Missouri: Sen. Jim Talent is one of five Republican incumbents in particularly tough races. His challenger is State Auditor Claire McCaskill.
Montana: Sen. Conrad Burns, a three-term incumbent Republican, trails Democrat Jon Tester, president of the state Senate, in pre-Labor Day polls.
Nebraska: First-term Democratic Sen. Ben Nelson defends his seat in a Republican state against wealthy businessman Pete Ricketts.
Ohio: Republican Sen. Mike DeWine is in a highly competitive race against Democratic Rep. Sherrod Brown in Ohio, where President Bush and Gov. Robert Taft both suffer from lagging popularity.
Pennsylvania: Sen. Rick Santorum, a conservative and member of the GOP leadership, trails State Treasurer Bob Casey, his Democratic challenger, in the polls.
Rhode Island: Sen. Lincoln Chafee, a moderate Republican, faces conservative challenger Steve Laffey in a Sept. 12 primary. The survivor faces former state Attorney General Sheldon Whitehouse.
Tennessee: Majority Leader Bill Frist’s retirement clears the way for a race between Republican Bob Corker, a former mayor of Chattanooga, and Democratic Rep. Harold Ford, hoping to become the first black Southerner elected to the Senate in more than a century.
– The Associated Press
