The surge of voter enthusiasm for the Bernie Sanders campaign may not translate into Clinton fever this fall if she gets the nomination. According to the latest McClatchy-Marist poll, some 25% of Sanders supporters—especially independents, moderates, and men—say they won't support Hillary Clinton if she becomes the nominee. It's not clear whether they would vote Republican, choose a third-party candidate, or just stay home. Only 14% of Clinton supporters say they won't support Sanders if he becomes the nominee. "Right now, the Sanders voters are more reluctant to support a Clinton candidacy," says Lee Miringoff, director of the Marist Institute for Public Opinion.
The poll numbers are worrying news for the party, though Mediaite notes that during the 2008 Democratic primaries, pollsters found that 50% of Clinton voters claimed they would support John McCain over Obama, who ended up winning that November. The McClatchy poll also found that Sanders has edged ahead of Clinton nationwide, 49% to 47%, helped by overwhelming support among voters 29 and younger, 73% of whom prefer him to Clinton. He also leads among Latinos, independents, and the unmarried, while black voters, voters over 60, and Democrats lean toward Clinton. (Sanders believes his path to victory involves a contested Democratic convention.)