Conventional wisdom said that powerful Congressman Joseph Crowley couldn’t be beat. But his 20-year career in the House of Representatives will end in early January, with the socialist organizer who beat him in the Democratic primary in the deep-blue district poised to become Congresswoman Alexandria Ocasio-Cortez.

The defeat of Crowley shows how grass-roots movements can prevail against the corporate establishment and its vast quantities of cash. The Crowley campaign spent upward of $3 million in the Democratic Party primary. The Ocasio-Cortez campaign spent one-tenth as much. He wielded money power. She inspired people power.

As the 28-year-old Ocasio-Cortez was quick to say after her victory Tuesday night, the triumph belongs to everyone who wants social, economic and racial justice. She ran on a platform in harmony with her activism as a member of Democratic Socialists of America and an organizer for the Bernie Sanders presidential campaign.

In a simple and symbolic twist of fate, the stunning defeat of Crowley came a day before the Rules and Bylaws Committee of the Democratic Party voted on what to do about superdelegates.

Conventional wisdom said superdelegates—who exerted undemocratic power over the selection of the party’s presidential nominee in 2016—couldn’t be stopped from putting the establishment’s thumbs on the scale again.

But on Wednesday afternoon, the party committee approved a proposal to prevent superdelegates from voting on the presidential nominee during the first ballot at the 2020 Democratic National Convention. (The last time the party’s convention went to a second ballot was back in 1952.)

As NPR reported, “A Democratic National Committee panel has voted to drastically curtail the role ‘superdelegates’ play in the party’s presidential nominating process. The DNC’s Rules and Bylaws Committee voted 27 to 1 to block officeholders, DNC members and other party dignitaries from casting decisive votes on the first ballot of presidential nominating conventions.”

Make no mistake: Those in the top echelons of the Democratic Party aren’t moving in this direction out of the goodness of their hearts. Grass-roots pressure to democratize the party—mounting since 2016—is starting to pay off.

But that pressure needs to increase. Corporate power brokers of the national party are in the midst of a tactical retreat, which should not be confused with surrender.

During the latest Rules and Bylaws Committee meeting, former DNC Chairs Donald Fowler and Donna Brazile voiced strong—and in Fowler’s case, bitter—opposition to changing the superdelegates status quo. They may have been foreshadowing an escalation of insider pushback before the full DNC decides on rules in late August.

In recent weeks, some of Crowley’s kindred corporate Democratic colleagues in the House—angry at the prospect of losing their privilege to vote on the nominee at the next national convention—have been railing against the superdelegates reform proposal. Rep. Gerry Connolly of Virginia said that “it disenfranchises the elected leadership of the party” and, if adopted, “is going to do terrible damage to party harmony.”

A New Jersey congressman, Bill Pascrell, said: “I think this is absolutely an insult to us. We’re no better than anybody else, but we stand for election. That has to mean something, that has to stand for something. That’s a lot of baloney.”

DNC Chairman Tom Perez has become an advocate for blocking superdelegate votes on the first ballot. That has put him in the line of fire from Capitol Hill, as Politico reported in early June: “Rep. David Price (D-N.C.), executive director of the early-1980s Hunt Commission, which created superdelegates, said lawmakers were ‘infuriated’ by Perez’s stance, although he’s not sure there’s anything that can be done. ‘I think there was a good deal of incredulity and some pretty severe criticism,’ Price said.”

Very few entrenched Democratic officials were willing to criticize the setup when most of the 712 superdelegates made Hillary Clinton the far-ahead “front-runner” by announcing their support for her before a single ballot was cast in a primary or caucus to choose the 2016 nominee.

Now, the huge defeat of quintessential hack Crowley by Ocasio-Cortez underscores the importance and the possibilities of what Bernie Sanders urged during a recent video interview: “Open the doors of the Democratic Party. Welcome working people. Welcome young people in. Welcome idealism in.”

Of course, “idealism” is hardly a word that comes to mind when listening to Democratic congressional leaders like Nancy Pelosi, Chuck Schumer and Crowley. No wonder young people’s support for the party has been eroding.

“It may take liberals by surprise to hear that a recent Reuters/Ipsos mega poll of 16,000 respondents found that the Democrats are losing ground with millennials” even while “their support for Republicans has remained roughly stable,” Guardian columnist Cas Mudde wrote days ago. “While millennials still prefer the Democratic Party over the Republicans, that support is tanking. In just two years, it dropped sharply from 55 percent to 46 percent.”

Reviving the Democratic Party will require making the party democratic in the process of winning genuine progressive victories. Ocasio-Cortez is helping to show the way.