Back in early February, on the night of the Nevada Democratic caucuses, Bernie Sanders backer Ranald Adams was watching CNN while scrolling through liberal blogs like Current Affairs and Jacobin. A month earlier, Adams had decided to skip his spring semester at the University of North Carolina at Chapel Hill and drive to New Hampshire to join the legions of young volunteers knocking on doors and making phone calls for the Vermont senator. When Bernie won big, Adams says, it felt like he’d blown “a breath of fresh air into political discourse.”

Now it was ten days after that exhilaration, that glimmer of hope that, yes, Bernie could win. As he watched the results roll in from Nevada, Adams saw Sanders supporters calling foul online, claiming that the Democratic leadership had hijacked the proceedings and disqualified several dozen Sanders delegates—charges that are still hotly disputed. “If the Clinton campaign is willing to win by such measures, why should I support them?” Adams remembers thinking. At that moment, he says, he decided to vote for someone other than Clinton if she won the nomination.

Adams is hardly alone. According to a YouGov poll conducted in early May, 45 percent of Sanders supporters have no plans to vote for Clinton in the general election. The choices these voters ultimately make will go a long way toward deciding whether Clinton can rekindle the young, diverse coalition that elevated Barack Obama to victory. It’s a pressing question for Democrats: Where will the sprawling network of Sanders volunteers, activists, and coders channel their energies if Clinton, as expected, secures the nomination?

The choices these voters ultimately make will go a long way toward deciding whether Democrats can rekindle Obama’s young, diverse coalition and win.

Publications from Politico to People magazine have floated the idea that some Sanders supporters will back Donald Trump in the general election. Others may gravitate toward Libertarian Gary Johnson, the former New Mexico governor who said after winning his party’s nomination last weekend that he sides with Sanders “73 percent of the time.” But laissez-faire libertarian economics won’t likely go down much better with former supporters of a democratic socialist than Trump’s white-nationalist rhetoric.

The more logical #NeverClinton option, especially for Sanders’s cadre of young idealists, has so far attracted little attention: Green Party candidate Jill Stein. The doctor and environmental activist from Massachusetts, making her second run for president, is even more of a long shot than Johnson—in 2012, she garnered just one-half of one percent of the vote. But I recently spoke with a handful of young, disaffected Sanders supporters like Adams who say they’re leaning toward Stein. They resonate with her calls to break up the banks, transition to 100-percent renewable energy, and slash military spending by half. The main factor working in Stein’s favor, though, are doubts about the sincerity of Clinton’s progressivism—and the clear itch to find a full-throated anti-establishment champion.