If Donald Trump or Ted Cruz wins the White House, a well-organized contingent of progressive activists could act as an opposition force. If Clinton wins, the same political network could be activated to push her further towards the political left. Even in the long-shot scenario of a Sanders win, a strong grassroots movement might be needed to pressure Congress to embrace his agenda. No matter what happens, an engaged grassroots could help elect like-minded candidates in state and local races.

A conversation over the future of Bernie’s grassroots army is already playing out in public view. Erik Forman, a Bronx high school teacher, union activist and Sanders supporter, recently published a letter on Medium urging the candidate to think about how to create a lasting political movement out of the campaign. More than a thousand people have so far signed on. “My hope is that this is the beginning, and not just a flash-in-the pan presidential campaign around one very adorable 74-year-old socialist,” Forman said.

A number of progressive organizations backing Sanders are planning to convene a summit in Chicago this summer before the Democratic national convention in July. “When he is no longer competing for primary votes, when that happens, all the people who have been killing themselves phone banking and canvassing and donating, they’re going to be like, ‘okay now what?’,” said Charles Lenchner, the co-founder of pro-Sanders group the People for Bernie Sanders. “I would like us to come out of that summit with a very clear idea of how we’re going to push for concrete victories regardless of who the nominee is.”

Still, any discussion of the future that plays out in public risks sparking disagreement that could fracture the movement. Efforts by Sanders allies to plan for what comes next while the campaign focuses on winning states and delegates could lead to a mutually-beneficial division of labor. But if the campaign feels that forward-looking talk is turning into a distraction, or dislikes the ideas put forward, that could cause friction. (The campaign did not offer comment for this story). It could also open supporters up to criticism that they aren’t channeling every ounce of available energy into helping Sanders win the White House.

“I think there’s a really interesting tension that is completely natural that you can already see between the Sanders campaign and the independent support for Sanders,” Svart commented. “Bernie definitely supports a long-term movement, but when you’re a candidate or working for a candidate you basically have one real core goal and that's to win.”

Then there’s the question of where Sanders fits into a long-term vision for the future. It’s not clear that Sanders would want to act as a leader of any kind of institutional movement. The idea of the senator as a political powerbroker could also clash with his populist anti-establishment image.