The final battle of the 2016 Democratic primary process is on. This will come as news to practically everybody: Didn’t Hillary Clinton fend off Bernie Sanders at long last, then woo his support successfully with platform concessions that moved the party further left? Yes, and yes. But there is one more big grassroots-versus-establishment clash remaining to be settled before next week’s Democratic National Convention—or, possibly, during next week’s convention.

Last Thursday, a coalition featuring supporters of both Hillary Clinton and Bernie Sanders notified the Democratic National Committee that they will formally introduce a plan to the Rules and Bylaws Committee to eliminate superdelegates, the 712 party leaders and elected officials who hold a vote in the presidential nominating race. The coalition wants the nomination to only be decided by primary voters, not party poohbahs free to vote for whomever they want.

Fourteen progressive groups are behind the proposal, which can be found at “The superdelegate system is unrepresentative, contradicts the purported values of the party, and reduces the party’s moral authority,” they wrote the DNC. Organizers expect between 100,000 and 200,000 to use activist tools at the website and take action this week—including direct appeals to Rules Committee members on social media.

In many respects, this push is one more extension of 2016’s historic challenges to the political establishment. The DNC invented superdelegates in the 1980s as an explicit safety valve for party elites on the nominating process. Sanders supporters have railed against the role of superdelegates for the entire primary, pointing out the stark difference between Democratic rhetoric about being the party of the people and the way that unelected insiders help decide the nominee. Consigning superdelegates to the dustbin of history could help win the war for the soul of the Democratic Party, even though pro-Sanders forces lost the battle.

Which is why, at first glance, this might sound like a doomed effort. It’s rare to see activists have a real effect on party organization; the decisions are typically made at too high a level for those on the outside to find leverage. (That doesn’t just go for the Democrats, of course, as Monday’s last, hapless crash-and-burn effort by the #NeverTrump cadres at the RNC showed.) And in this case, to be successful, many superdelegates would have to affirmatively vote to relinquish some of their power. Indeed, superdelegates affiliated with the Congressional Black Caucus have already announced their opposition to any changes, arguing that it would dilute their influence over party operations.

The last successful insurgent upending of the Democratic Party structure was a long time ago, back in 2005. But that was no small thing— it elected Howard Dean as DNC chair. And the superdelegate fight shares some important similarities with the campaign to install Dean. Namely that—contrary to all appearances and expectations—this is not just another predictable square-off between party rebels and elites.

DNC members elected Dean to lead them in 2005 because lots of them were Dean supporters. They’d won election inside their states and taken over the party. So the tens of thousands of citizens clamoring for Dean to become chair found sympathetic ears in decision-making positions. Those tweeting at Rules Committee members to axe the superdelegates will see similar friendly faces this year. And they won’t all be Bernie people.

The action begins before the convention. Today, Rules Committee member and Rhode Island State Representative Aaron Regunberg will file the proposal to end superdelegates, stating that all delegates should be selected through the popular vote in the states. The change would apply to the 2020 nomination and beyond, but not to 2016. (No last-ditch #NeverHillary effort here.)

The Rules Committee meets to finalize party nomination rules on Saturday. EndSuperdelegates claims that more than two dozen of the 187 Rules Committee members will co-sign the Regunberg proposal. That doesn’t seem far-fetched, considering that even Barney Frank, the chair of the committee, endorsed eliminating superdelegates last month. He has said that he expects a robust debate on the matter, which also doesn’t seem far-fetched.

If the Rules Committee agrees to the Regunburg proposal, it will likely be passed by acclamation at the convention without a fight. If they shoot it down, you can expect a fight on the floor to get all delegates on the record.

As Frank’s position shows, the issue won’t come down to a predictable Sanders-Clinton divide. In their initial announcement, EndSuperdelegates featured statements from prominent endorsers of Secretary Clinton. “If we want the voice of everyday people to be louder and more consequential in our nation’s politics, it must also be so in our party,” said Simon Rosenberg of the New Democratic Network. Christine Pelosi, the Clinton supporter and political strategist who co-authored the resolution in the California Democratic Party that nullified most of the state’s superdelegates, added that “leaders should never trump the will of the voters.”

Several additional states, including Nebraska, Maine, and Wisconsin, passed resolutions at their state party conventions this spring urging changes to the superdelegate process. These are the people who will ultimately vote at the national convention. So the grassroots forces aren’t screaming into a black hole, but are unified with much of the party leadership, across the ideological spectrum.

About the only thing the reformers aren’t aligned on is how they actually want to handle the reform. EndSuperdelegates wants just what the name says: an end to the superdelegate process altogether. But there’s a surprising wild card in all this: Bernie Sanders, the man who has decried the presidential nominating process throughout his 2016 run.

Sanders has thus far supported a softer superdelegate reform, with a continued role for elected officials in the process. Interestingly, this puts him in a less extreme position than Barney Frank on this issue. “We have serious concerns, and I expect some of those concerns to end up on the floor of the convention,” Sanders told The Washington Post last week. While the Sanders campaign has made its dissatisfactions known for months, negotiations between representatives and the Rules Committee to hash out the details have only recently begun.

A compromise option on superdelgates, which I’ve floated here, would be to give them a seat at the convention, but not let their votes for the presidential nominee count on the first ballot. That way, experienced party leaders could take part in convention activities and perhaps in a particularly close and unsettled race. But barring the extremely unusual, the nominee with a majority of delegates from primary elections would emerge victorious, straight up.

Frank endorsed a form of this compromise in June. “My own view would be that the people who qualify as ex-officio delegates,” another word for superdelegates, “should be allowed to attend the convention but not vote,” he said.

There are likely to be other Rules Committee fights over efforts to democratize the process: whether to open primaries up to independents, whether (and how) to encourage states to hold primary elections instead of caucuses. But the superdelegate fight has the greatest likelihood of success, because the role is completely in the control of the DNC, in a way that state-by-state election rules aren’t. And the combination of grassroots pressure and insider agreement could finally bring down the least democratic institution in the Democratic Party, in just a week’s time.