Several networks declared Sanders the winner about two hours after polls closed.
Clinton still holds a significant lead in delegates, but Sanders has vowed to take his fight all the way to the Democratic National Convention in Philadelphia. Even if his chances are long in securing the nomination, his victories at the end of the primary process could expand his influence as Clinton tries to turn her attention to the general election.
Clinton’s campaign has increasingly set its sights on Trump, even as Sanders has won recent primaries. The tone of the race between Clinton and Sanders has gotten acrimonious among some of their supporters, as Clinton backers worry about party unity and Sanders’ backers resist the notion that the race is over and he should call it quits.
On Monday, Susan Sarandon, a surrogate for Sanders, generated some criticism when she told Larry King that she was still not ready to say she’d vote for Clinton over Trump, while also bringing up the possibility of Clinton having “health issues.”
Clinton’s defeat in West Virginia is a reversal from 2008, when she handily beat Barack Obama even as he held a delegate lead. That was insurmountable, and he went on to win the nomination even as he lost a number of states in the waning days of primary season.
Exit polls showed Sanders leading Clinton among voters who want a less liberal government than that of President Obama — a contradiction given that the Vermont senator has largely been running to Clinton’s left. But he has done well in states with lower percentages of minority voters.
Polling also showed that a significant chunk of Sanders supporters — 44% in a CBS News poll — would vote for Trump.
Clinton was the projected winner in a primary in Nebraska, but it does not factor in the delegate count.