The Democratic Congressional Campaign Committee warned political strategists and vendors Thursday night that if they support candidates mounting primary challenges against incumbent House Democrats, the party will cut them off from business.

The news was officially announced Friday morning, paired with a statement on the committee’s commitment to diversity in consulting — “which, obviously, is just to give themselves cover,” a Democratic political consultant who learned of it Thursday told The Intercept. The consultant asked for anonymity given their relationship with the DCCC, and the party organization’s professed strategy of blacklisting firms that don’t fall in line.

To apply to become a preferred vendor in the 2020 cycle, firms must agree to a set of standards that includes agreeing not to work with anyone challenging an incumbent.

“I understand the above statement that the DCCC will not conduct business with, nor recommend to any of its targeted campaigns, any consultant that works with an opponent of a sitting Member of the House Democratic Caucus,” the form reads.

It’s no secret that the DCCC and national party leaders often interfere on behalf of preferred candidates. Or that they otherwise jump into the game too late, if they don’t completely write off newcomers who don’t meet their standards. The DCCC is known for prioritizing candidates and direct them to its own consultants, most of whom are alumni of the DCCC, which is known in Washington as a “consultant factory.” The latest move only reaffirms that reputation and sends a warning shot to grassroots and progressive consultants.

Groups working to diversify Congress say the committee has been slow to adequately address lack of representation — i.e., recruiting more women and people of color. Collective PAC, which works to elect black Democrats, sent a letter to the DCCC last year asking why the group didn’t include any black candidates in its “Red to Blue” program, which targets seats that have a promising chance to flip. They added several candidates after that, including current Reps. Lauren Underwood of Illinois and Colin Allred of Texas.

D-trip claims its top priority is protecting the majority, and that in order to do so, they must keep internal discord at a minimum. But as progressive candidates, organizers, and members build grassroots campaigns and prove they can hold their own, the D-trip’s old playbook is having the opposite effect.

The strategy isn’t new. Though it did bring a few more hiccups in 2018 than expected, which makes the rollout all the more puzzling. “There was never an enforcement that I’ve ever seen,” the strategist told The Intercept. “This is the first time that they are ever making it open policy.”

After their coordinated attack on Laura Moser in Texas’s 7th District, she raised $86,000, got an endorsement from Our Revolution, and made it to a runoff. She eventually lost to current Rep. Lizzie Fletcher. But the episode gave fodder to progressive groups like the Working Families Party, Justice Democrats, and Collective PAC, which had formed for precisely that occasion — the party’s increasing inability to make space for new voices, many of them progressive. D-trip proved their point, and Our Revolution and WFP stepped in instead.

And in Nebraska’s 2nd District, the DCCC backed former Rep. Brad Ashford over Kara Eastman, who ended up winning the primary and losing the general election. Ashford was a former Republican who flip-flopped on access to abortion throughout his time in the state legislature and later as a Democrat in the U.S. House, and opposed single-payer health care. Eastman was a staunchly pro-choice progressive who supported Medicare for All. She was one of only two insurgents to beat DCCC-backed candidates last cycle. In the Democratic primary for Kentucky’s 6th District, Amy McGrath beat Jim Gray and later lost to Republican Rep. Andy Barr. Senate Minority Leader Chuck Schumer is now recruiting her to run against Majority Leader Mitch McConnell in 2020.

Strategists and congressional staffers with knowledge of the change say it will disproportionately impact vendors and candidates who are women and people of color, as the consultants who work with incumbents are the ones who’ve come up through the party at a time when its commitment to diversity was even dimmer than it is today.

The committee is telling firms they can’t oppose sitting members, the strategist said. “I’d rather keep the majority too, which is why to me this is kind of stupid to have a blanket rule. Because, if it’s a safe incumbent seat, why does it matter?”