Both candidates have seen their leads grow and shrink with the presidential candidates. It's very likely the winner of the Senate seat will be a member of the same party of the presidential candidate who wins Virginia's 13 electoral votes.

Washington: Sen. Maria Cantwell (D) vs. Michael Baumgartner (R)

Democrat Maria Cantwell is expected to win a third term in November. She faces Republican state Sen. Michael Baumgartner.

West Virginia: Sen. Joe Manchin (D) vs. John Raese (R)

No, we did not forget to update this section from 2010. Democrat Joe Manchin once again faces Republican businessman John Raese in the contest to win his first full term. Manchin has proven his independence from the president and faces a much easier race this time to win in November.

Wisconsin: Rep. Tammy Baldwin (D) vs. former Gov. Tommy Thompson (R)

Open seat -- Sen. Herb Kohl (D) is retiring

Former Gov. Tommy Thompson won a tough Republican primary to take on seven-term Democratic Rep. Tammy Baldwin for retiring incumbent Herb Kohl's Senate seat. Thompson's attacks on Baldwin as being too liberal haven't had the impact he was hoping. The polls are very close, but Baldwin has pulled slightly ahead recently, though not outside the margin of error.

Unless vice presidential candidate and native son Paul Ryan brings out strong turnout for the party, the state's historic Democratic tilt in presidential elections could help Baldwin succeed to becoming the first openly gay senator.

Wyoming: Sen. John Barrasso (R) vs. Tim Chesnut (D)

Republican John Barrasso is expected to win a second term in November. He faces Democratic nominee Tim Chesnut, an Albany County commissioner.