Bella Abzug, who brought the feminist movement to Congress with her message that “a woman’s place is in the House,” arrived on the national stage after beating a New York Democratic incumbent in a 1970 primary.

Ron Dellums, one of the most principled advocates for peace ever to sit in the US House of Representatives, won his seat by defeating a California Democratic incumbent in a 1970 primary.

Elizabeth Holtzman, an essential defender of the system of checks and balances and the Bill of Rights during her time in the Congress, came to Washington after beating the dean of the House of Representatives in a 1972 New York Democratic primary.

These historic figures are only a few of the Democrats who came to Congress not as the choices of party leaders but as champions of the grassroots activists who helped them defeat entrenched Democratic congressmen in primaries. Many of the most dynamic figures in the history of the Democratic Party got their start by taking on incumbents in primaries. Even some who do not succeed in their primary challenges go on to big things—Barack Obama’s first bid for federal office was a 2000 primary race against Democratic Congressman Bobby Rush.

Primary races against incumbents have historically been the avenue through which bold young Democrats get a chance to challenge not just their party but a political process that erects too many barriers to new candidates and new ideas. Those barriers exist because the prospect of change unsettles party bureaucrats, who seek to maintain their own grip on power by writing rules that benefit them.

So no one will be surprised that, as a new generation of insurgent reformers steps onto the political stage, the defenders of politics-as-usual are worried. They’re uncomfortable with the fact that many of the most prominent newer members of the House—including California Congressman Ro Khanna, Massachusetts Congresswoman Ayanna Pressley, and New York Congresswoman Alexandria Ocasio-Cortez—beat Democratic incumbents in primaries. And they worry that more incumbents will be challenged in 2020.

Whatever self-serving spin may be conjured by party leaders and their amen corner in the media, this is the explanation for why the Democratic Congressional Campaign Committee has announced that it will not grant contracts to pollsters, strategists, and communications specialists working with Democrats who mount primary challenges to incumbents in 2020. And this is why politically-savvy Democrats are objecting to the DCCC’s move.

“This runs counter to anything that would be considered democratic in a small ‘d’ sense,” says Congressional Progressive Caucus co-chair Mark Pocan (D-WI). “It sends exactly the wrong signal to all the young people, all the people who are getting involved in politics, who the Democratic Party should be trying to attract.”

Pocan is a well-regarded campaigner who has worked closely with the DCCC over the years. Yet, he says the latest move by the campaign committee “does nothing positive toward advancing the goal that the DCCC says that it seeks to achieve: which is electing more Democrats to the House.”

Pocan is working with CPC co-chair Pramila Jayapal (D-WA) to get the DCCC to reverse course. But, so far, DCCC chair Cheri Bustos (D-IL) has refused to bend. “We’ve got a policy that the caucus supports, the leadership supports, and it plays the long game,” says Bustos. Jayapal counters that “It is not playing games for the Democratic party to be inclusive of all its members’ perspectives.”

Ocasio-Cortez, who decries the DCCC rule as a “blacklist+boycott” policy, warns that it is “extremely divisive (and) harmful to the party.”

It is also ineffective. This week, major progressive groups endorsed Marie Newman’s 2020 Illinois primary challenge to Democratic incumbent Dan Lipinski. Newman, a progressive, supports abortion rights. Lipinski, one of the most conservative Democrats in the House, does not. Announcing NARAL Pro-Choice America’s endorsement of Newman, NARAL president Ilyse Hogue said, “We must double down on basic human rights now. We cannot support oppression even if they have a D next to their name.”

MoveOn, Planned Parenthood Action Fund, the Progressive Change Campaign Committee, and Democracy for America have joined NARAL in endorsing Newman. A number of other groups, including Emily’s List, are supporting Newman, who came within two points of defeating Lipinski in a hard-fought 2018 primary.

Instead of shying away from the contest in Illinois, and other contests like it, progressive groups are getting in early. At the same time, some of the party’s most engaged activists are stepping up to argue that the party must be open to change.

“We are stakeholders in the future of the Democratic Party,” says Ruby Schneider, chair of the University of Michigan College Democrats, which played an important role in shifting the partisan politics of a key battleground state in 2018. “We want to see a party that reflects diverse identities and is open to change.”

College Democrats on more than 60 campuses have signed a statement that declares: “Primary challengers are essential to ensure that the Democratic Party is continually held accountable to the needs of our constituents.”

That is a sentiment that is being voiced with increasing frequency by activists and groups that work on behalf of economic, social, and racial justice.

“We should celebrate, not blacklist, people who want to lift up a new generation of progressive leadership instead of protecting corporate Democrats,” says Nelini Stamp, the director of strategy and partnerships for the Working Families Party. “We can only build a government that works for working people if we elect progressive candidates who come from the grassroots—and that includes supporting primary challengers.”

Color of Change’s Rashad Robinson says, “Competitive primary challenges are a way to give Black voters the power to hold incumbents accountable in their communities. And primary challenges are how Black people have been able to lift up issues like police misconduct, voting rights, and access to education in recent elections. We reject the DCCC’s new divisive policy, and will challenge any elected official—incumbent or otherwise—who doesn’t stand up for Black people.”

The critics of the blacklist are right. The Democratic Party cannot afford to narrow its options at this point. In order to define itself as more than just “not the GOP,” the party has to become more boldly progressive, most ideologically energetic, and more diverse. The smart strategists know this. That’s why a number of them have joined Rebecca Katz, the founder of New Deal Strategies, in announcing that they will not let the DCCC intimidate them. “As a loyal Democrat and proud progressive, I believe that we don’t just need more Democrats in Congress—we also need better Democrats in Congress,” says Katz. “I won’t hesitate to work with progressive candidates challenging incumbent Democrats who are out of touch with their constituents. If that means getting blacklisted by the DCCC, then so be it.”

This willingness on the part of activist groups and strategists “to work on progressive primary challengers to incumbent, out-of-touch Democrats this cycle” represents an “unprecedented” rejection of the DCCC’s heavy-handed approach, argues Justice Democrats executive director Alexandra Rojas.

“The DCCC implemented their policies to prevent progressive primary challengers like Alexandria Ocasio-Cortez and Ayanna Pressley from going ‘mainstream’ in 2020,” says Rojas, “but it looks like the exact opposite is happening.”