West Virginia Democratic primary
Voting: 6:30 a.m. to 7:30 p.m. EDT
At stake: 28 pledged delegates
The race: It's a must-win for Hillary Clinton, and she needs to win overwhelmingly to keep her faint hopes alive and to strengthen her rationale to buck daunting mathematical odds. Luckily for her, the state's key voting blocs align closely with her core supporters: working-class, white, rural, and older voters. Polls show her with a lead as large as 36 percentage points over Barack Obama. He could win support among independents, who are being allowed to vote in the Democratic primary for the first time. He has the backing of US Senator Jay Rockefeller, but is looking ahead to the more friendly ground of Oregon on May 20. Both candidates are seeking the support of the influential United Mine Workers.
