WASHINGTON — The House Democratic campaign arm is on the verge of open warfare with the party’s rising liberal wing as political operatives close to Speaker Nancy Pelosi try to shut down primary challenges before what is likely to be a hard-fought campaign next year to preserve the party’s shaky majority.
Progressive Democrats were infuriated last month when Representative Cheri Bustos of Illinois, the chairwoman of the campaign arm, the Democratic Congressional Campaign Committee, moved to protect centrist incumbents by formally breaking committee business ties with political consultants and pollsters who go to work for primary challengers.
Representative Alexandria Ocasio-Cortez, Democrat of New York, who owes her seat to a successful primary challenge, went so far as to encourage her 3.8 million Twitter followers to “pause” their donations to the campaign committee in protest.
Ms. Bustos’s rule prohibits Democratic consultants and vendors working for a primary challenger to an incumbent from receiving work from the committee. It comes as ardent liberal organizations such as Justice Democrats, emboldened by a pair of high-profile wins in 2018 — Representative Ayanna Pressley of Massachusetts and Ms. Ocasio-Cortez — are aggressively gearing up to challenge centrist or old-line Democrats with liberal candidates.
In the latest swipe in a fight that has erupted into open hostilities, a coalition of progressive groups on Friday introduced an online database of go-to vendors for insurgent candidates emblazoned with the heading, “Despite the D.C.C.C.’s bullying, we’re still going to work on primaries.”
One group, the Progressive Change Campaign Committee, said Friday that it was exploring a challenge against Representative Richard E. Neal of Massachusetts, the chairman of the powerful Ways and Means Committee, because he has not committed to holding hearings on the single-payer health care system known as “Medicare for all.” At the helm of that panel, Mr. Neal has been on the front lines of conducting oversight on President Trump’s finances, and last week requested six years of his personal tax returns.
“We reject the D.C.C.C.’s attempt to hoard power, which will only serve to keep that talent pool — and Congress itself — disproportionately white and male,” María Urbina, the national political director for Indivisible, a progressive grass-roots group, said of the campaign committee. “Incumbents who engage fully with their constituents shouldn’t fear primaries and shouldn’t rely on the national institutions like the D.C.C.C. to suppress challenges before voters ever have a say.”
Party leaders and the campaign arm have stood by Ms. Bustos’s moves, arguing that the committee’s mandate is to protect the new majority by protecting incumbents — and that putting a longstanding rule in writing simply increases transparency. Primary challenges, even in solid Democratic districts, harm the mission of holding the majority, they argue, because incumbents fighting a primary challenge cannot raise money and help other Democrats in more marginal districts.
“I support the notion that the primary purpose of the Democratic Congressional Campaign Committee is to elect Democrats in tough districts, so we can either win the majority or hold the majority,” said Representative Hakeem Jeffries of New York, the No. 4 Democrat.
A spokesman for the committee said that Ms. Bustos, who hails from a Midwestern district that voted for Mr. Trump in 2016, was fulfilling a campaign promise she made to Democrats that as the chairwoman, she would support incumbents. And some at the campaign arm are frustrated that the codification of the longstanding policy has received more attention than the enforcement of a new rule that requires vendors to meet certain diversity standards, including employing more racially diverse, veteran, lesbian, gay, bisexual, transgender or disabled staff.
The new policy is unlikely to change. But the ire from the left flank may only grow.
“Primaries are often the only way that underrepresented and working-class people are able to have a shot at pursuing elected office,” Ms. Ocasio-Cortez said. “I think that it can reduce the odds of us getting really strong representation. We need to have kind of a farm system for the next generation.”
Other House Democrats, such as Representative Mark Pocan of Wisconsin, a leader of the Congressional Progressive Caucus, are taking a cooler tone. But on Thursday, he could not resist a jab at Ms. Bustos on the radio program “The Bill Press Show.”
“We were trying to keep this in the family, but unfortunately this morning, I saw Cheri Bustos, after she asked us not to do it publicly, came out and decided to talk about it,” he said. “The progressive caucus doesn’t go out and recruit people to run against incumbents, but I think it looks awful for the Democratic Party to be undemocratic.”
“It’s the wrong path for us to be taking,” he continued. “This was a misguided action, and rather than review it, she’s trying to double down on it.”
The decision has pleased moderates and veterans in the more centrist New Democrat Coalition, in the Blue Dog Coalition, a fiscally conservative group of Democrats, and in the Congressional Black Caucus, who have been angered by some of the incumbents that outside liberal groups have chosen to target. Many of the candidates wooed in the last campaign cycle by Justice Democrats would have run in districts that lean Republican. The Democratic Congressional Campaign Committee had to work hard to beat those challenges back, worried that a triumph by Justice Democrats in the primary would have cost the party a possible victory in the general election.
Defending the campaign arm’s decision, Representative James E. Clyburn of South Carolina, the majority whip, recalled a past primary against Representative Bennie Thompson, Democrat of Mississippi.
“An African-American got in the race against him running to his right and then he looked up and there was this Democratic pollster working for his opponent,” Mr. Clyburn told National Journal. “He’s paying dues to the D.C.C.C., who’s giving a contract to that person and then that person ended up working for that opponent. There’s something wrong with that.”