Polls are open in West Virginia, and election officials say things are off to a smooth start.
Hillary Rodham Clinton is expected beat rival Barack Obama by double digits, and score another victory in next week's Kentucky primary.
But Obama has spent little time campaigning in either state, focusing more on his anticipated run against John McCain.
Clinton appears to be pinning her hopes on strong showings in the next two states to press her case that Obama is weak among key Democratic constituents.
Clinton has been pointing out that no Democrat has won the White House since 1916 without winning in West Virginia. Campaigning in Fairmont, the former first lady urged residents to get to the polls because, in her words, "this may be the most important vote you've ever cast."