2004 results: Sen. Kerry won the state's four electoral votes with 60% of the vote.
A well-known Republican in a conservative state, Sen. Lindsey Graham would likely have little to fear from Democratic challengers. Instead, Republicans unhappy with his support of a failed immigration overhaul plan are lining up to oppose him. Those running or considering a run include state Rep. Jeff Duncan, computer specialist Tim Carnes, Air Force veteran John Cina and Gary McLeod, who has made unsuccessful runs for the House of Representatives.
2004 results: President Bush won the state's eight electoral votes with 58% of the vote.
Despite a life-threatening brain hemorrhage in December that kept him away from Congress for nine months, Democratic Sen. Tim Johnson says he will run again in 2008. Johnson won his last re-election bid by only 524 votes, and state Rep. Joel Dykstra and businessman Sam Kephart are competing for the Republican nomination to oppose him. Johnson is still undergoing therapy. No Democratic presidential candidate has won South Dakota since Lyndon Johnson in 1964.
2004 results: President Bush won the state's three electoral votes with 60% of the vote.
Actor and former senator Fred Thompson waited until September to declare his candidacy for the Republican presidential nomination, and he is relying on his home state to help him catch up in fundraising. More than one-fifth of the $12.8 million Thompson has raised has come from Tennessee.
GOP Sen. Lamar Alexander, who took the seat Thompson left in 2002, has no declared opponent yet in his re-election bid.
2004 results: President Bush won the state's 11 electoral votes with 57% of the vote.
After former House majority leader Tom DeLay, a Republican, was indicted on money-laundering charges and resigned, Democratic Rep. Nick Lampson won his seat in 2006. A half dozen Republicans are campaigning to take back the heavily Republican district. Democratic Rep. Ciro Rodriguez, who unseated Republican Rep. Henry Bonilla in a December 2006 runoff election, could also face a tough re-election bid.
Sen. John Cornyn's re-election bid will get a boost from President Bush, who plans to appear at a fundraiser for him this month. Democrats Mikal Watts, an attorney who contributed $7.5 million of his own money to his campaign, and state Rep. Rick Noriega are competing to oppose Cornyn.
2004 results: President Bush won the state's 34 electoral votes with 61% of the vote.
Republican Rep. Chris Cannon could face strong challenges from members of his own party unhappy with Cannon's support of President Bush's immigration overhaul plan. David Leavitt, an attorney with more than twice the campaign cash as Cannon, and Jason Chaffetz, former chief of staff to Republican Gov. Jon Huntsman Jr., will challenge Cannon in the primary. As one of the country's most popular governors, Huntsman is not expected to have a difficult re-election bid.
2004 results: President Bush won the state's five electoral votes with 72% of the vote.
The state backed Sen. John Kerry in the 2004 presidential election, and Vermont's congressional delegation consists of two Democrats and an independent socialist. But the state's governor, James Douglas, is a Republican and Democrats have yet to find a candidate to oppose him in 2008.
2004 results: Sen. Kerry won the state's three electoral votes with 59% of the vote.