When every 2020 candidate but Bernie Sanders said at last week’s debate that superdelegates should help pick the party nominee if no candidate reaches a majority of pledged delegates, supporters of the progressive frontrunner pounced. “[Sanders] was the only candidate with the RIGHT ANSWER,” surrogate Linda Sarsour tweeted. “Let the will of the people prevail.”

But during an exchange with a Sanders supporter in a CNN town hall Wednesday evening, fellow progressive Elizabeth Warren defended the primary process—helpfully pointing out that Sanders, himself, had staked his 2016 hopes on superdelegates intervening if Hillary Clinton didn’t win the majority of pledged delegates.

“Can you explain why the will of the voters should not matter if no candidate reaches a majority of delegates?” a self-identified Sanders backer asked Warren, describing the idea of a brokered convention as “undemocratic.”

“You do know that was Bernie’s position in 2016?” she replied.

“That was Bernie’s position in 2016—that it should not go to the person who had a plurality,” Warren continued. “And remember, his last play was to superdelegates. So the way I see it is, you write the rules before you know where everybody stands, and then you stick with those rules.”

Though the applause line didn’t go over well with Sanders’ most aggressive online supporters, who began calling for a primary challenger to the Massachusetts senator on Twitter, it pointed at how Sanders’s 2016 primary strategy against Clinton may have helped lay the groundwork for the controversial strategy being embraced by 2020 candidates seeking to nab the nomination from him. When he trailed Clinton in 2016, Sanders saw convention superdelegates as his last-ditch path to victory; however “undemocratic” he felt they were, they should decide the nominee if no candidate reached the delegate threshold—especially if he entered the convention that cycle with momentum from more recent primary wins. “We can argue about the merits of having superdelegates,” Sanders’s campaign manager Jeff Weaver said at the time. “But we do have them. And if their role is just to rubber-stamp the pledged-delegate count then they aren’t really needed. They’re supposed to exercise independent judgment about who they think can lead the party forward to victory.”

Sanders, now the frontrunner, has changed his tune since then. But that’s essentially the strategy that moderates, along with Warren, are pursuing as the Vermont senator builds momentum—and a delegate lead—in the nation’s first contests. Michael Bloomberg, the billionaire running as Sanders’s ideological opposite, has been the most transparent, reaching out to supporters of his moderate rivals to build a second-ballot coalition behind him—despite having yet to compete for a vote, carrying the heaviest baggage of any Democratic candidate, and stumbling when he’s ventured outside the controlled setting of ads, memes, and rallies. But it’s also likely the path to the nomination for the other candidates who remain in this primary race that will possibly not end with a candidate earning a majority of delegates heading into the convention in Milwaukee this summer.