Vote '06: The battle for Senate supremacy

Bush's political potency depends on Republicans hanging on to the Senate. There are 33 seats up for grabs, 15 of which are Republican. Democrats must gain six. These are the key contests in an election which has turned into a referendum on President Bush and his mission in Iraq

WASHINGTON STATE

Cantwell vs McGavick

Incumbent Democrat Maria Cantwell, the first in her family to graduate, squeaked a win in 2000, so the Republicans hope their Mike McGavick will oust her. But Cantwell should squeeze home.

MISSOURI

McCaskill vs Talent

The latest polls show Democrat Claire McCaskill and incumbent Republican Jim Talent are level. Vital for Democrats, but Republicans have only lost one Senate race in this state in 25 years.

CALIFORNIA

Feinstein vs Mountjoy

Incumbent Democrat Dianne Feinstein has been Senator since 1992, and was first woman to sit on Senate Judiciary Committee. She faces a challenge from Republican Richard Mountjoy.

MONTANA

Tester vs Burns

Long-serving Republican Senator Conrad Burns is mired in controversy over contributions from lobbyist Jack Abramoff. Democrat Jon Tester, a leading organic farmer, could take it.

RHODE ISLAND

Whitehouse vs Chafee

A heavily Democratic state, so it's likely that incumbent Republican Senator Lincoln Chafee will lose his seat to Democrat Sheldon Whitehouse, a former Attorney-General.

MINNESOTA

Klobuchar vs Kennedy

Democrat Amy Klobuchar takes on Republican Mark Kennedy - the fourth generation of his family to serve (and no relation to the JFK clan). This race could go either way.

VIRGINIA

Webb vs Allen

Republican Senator George Allen has watched his strong lead over Democrat Jim Webb slip amid controversy over racial slurs and his association with the Confederate flag.

CONNECTICUT

Lamont vs Lieberman vs Schlesinger

Ned Lamont won the primary from former vice-presidential candidate Joe Lieberman, who fights on as an Independent. Alan Schlesinger, a former mayor, is his Republican rival.

TENNESSEE

Ford vs Corker

Democrat Harold Ford Jr wants to be the first black senator elected in the South, but it won't be easy. This state tends to vote Republican; Democrats have struggled since 1994.

MARYLAND

Cardin vs Steele

Republicans hope to win with Michael Steele, first black man elected to statewide position in Maryland. Has to beat Ben Cardin, one of youngest Speakers in state's history.