WASHINGTON — A move by House Democratic leaders to thwart party members from mounting primary challenges to incumbents, even in safe Democratic districts, could have the unintended consequence of arresting the party’s shift toward a more female and racially diverse caucus, one of its most striking achievements of the last election.
This past week, a Democratic political consultant with longstanding ties to the party’s campaign committees quit a senior-partner position at the firm Deliver Strategies after it, like most dominant campaign outfits, agreed to comply with a Democratic Congressional Campaign Committee policy barring it from conducting business with a primary opponent of a sitting Democrat.
Her reason: She feared the policy’s impact on female challengers.
“It is hard enough for challengers, for a lot of reasons,” said the consultant, Amy Pritchard, who worked last year for Representative Ayanna Pressley, Democrat of Massachusetts, in her successful campaign to defeat a 10-term Democratic incumbent. “And this policy is a bridge too far. I’d like to see a majority of women in Congress, and it’s not going to happen with this policy.”
The D.C.C.C. is ostensibly out to protect sitting Democrats from having to worry about primaries, and instead focus their energy and money on fighting off Republicans. Some female and minority candidates did well in open primaries and beat Republican incumbents last year, even in majority-white districts. They will benefit from the new policy, even as many of them are critical of it.
But most insurgent Democrats set their sights on incumbents in safe Democratic seats, making the case that they are fresh faces who represent change. The new policy will most likely block candidates seeking to follow in the footsteps of Ms. Pressley, who is black, and Representative Alexandria Ocasio-Cortez of New York, who is of Puerto Rican descent, both of whom defeated veteran white male Democrats last year, Michael Capuano and Joseph Crowley.
Of the 50 longest-serving House Democrats, two-thirds are white and about the same share are men. Insurgents are often female, often young and often nonwhite, all groups that are part of the Democrats’ base strategy.
“I’ve worked in Democratic politics for 30 years, and as long as I have been around, I have never seen the D.C.C.C. engage in a primary as an institution on behalf of an incumbent,” said Ms. Pritchard, formerly of the firm Deliver Strategies, whose views are shared by a growing group of Democrats in and outside Congress.
“A lot of Democrats are terrified that what happened to Capuano and Crowley will happen to them and are looking for backup,” she said. “I actually thought this policy was a joke until I saw it written up, but they are enforcing it aggressively.”
Marie Newman came within two percentage points last year of defeating Representative Daniel Lipinski, an Illinois Democrat who is now in his eighth term and is one of the few in the caucus to oppose abortion rights.
She is running again, but two consultants have backed out of her campaign, “both citing the D.C.C.C. blacklist issue as the reason,” said Ben Hardin, Ms. Newman’s campaign manager.
Representative Diana DeGette, a Democrat who has served 12 terms in Colorado, is facing a primary challenge from Crisanta Duran, who was the first Latina speaker of the Colorado House of Representatives. “It is having a chilling effect on everyone’s capacity to move forward,” said Steve Welchert, a spokesman for Ms. Duran’s campaign and a veteran Democratic consultant.
Mr. Welchert said that one firm had rejected their business and that another firm said it was feeling pressure to do the same. “It certainly harms younger candidates,” he said, calling the policy “bullying.”
Suraj Patel, an adjunct professor at New York University and a former Obama administration staff member, got crushed in his campaign last year against Representative Carolyn Maloney, a longtime incumbent in New York. He wants to try again, hoping for an even larger turnout among young voters than last time, when their numbers soared.
But he already feels boxed out. “I have been officially told by three vendors that they could not work with me,” Mr. Patel said.
In New Jersey, Zina Spezakis, a clean technology investor, is taking on Bill Pascrell, who was first elected in 1996. While she found that the old-guard firms were not interested in her business, newer firms have popped up to help.
“It is a little maddening,” she said. “But there are a whole sector of firms willing to work with you. They are reflective of the candidates — younger, more creative and more efficient with their money.”
The argument for electing Democratic challengers is generally built around the notion that new faces and more diverse voices ought to replace old-timers. Most lose — for every Ms. Ocasio-Cortez who knocks down the House, there are scores of challengers who barely make a dent in the front door.
But in a year when women are once again expected to drive many races, an expanding group of Democrats outside Congress is critical of the D.C.C.C.’s decision. “I’m disappointed in the policy and don’t agree with it,” said Stephanie Schriock, the president of Emily’s List, which supports Democrats who favor abortion rights.
“We frequently work closely with the D.C.C.C. and will continue to do so,” she said. “But our top priority is electing pro-choice Democratic women, and sometimes that means being on a different side than the committees.”
Cole Leiter, a spokesman for the committee, defended the policy, pointing to the party’s success in last year’s midterm elections.
“The D.C.C.C. is proud of its historic work, flipping 43 formerly Republican seats and electing the most diverse caucus in American history,” he said. “The D.C.C.C. is already well into our work to fortify this newly won House majority and expand the battlefield further into districts that haven’t had the opportunity to elect a Democrat in decades.”
Primary battles have always vexed both parties, because they are divisive and because they drain incumbents’ coffers ahead of general election fights. But while Republicans have faced a spate of losses among incumbents during the Tea Party waves over the past decade, the committee that helps elect them to the House — the National Republican Campaign Committee — remains neutral in primary fights.
The D.C.C.C. policy has caused significant tensions among House Democrats. Many incumbents largely welcome the policy, but newer and more liberal members — especially those who have been shunned by the committee in their own races — are furious.
Ms. Ocasio-Cortez has encouraged donors to put their money elsewhere, and she has done her own online fund-raising for numerous candidates. “My recommendation, if you’re a small-dollar donor: pause your donations to DCCC & give directly to swing candidates instead,” she tweeted.
Representative Jahana Hayes, Democrat of Connecticut, ran for an open seat last year, but she said the policy could inhibit candidates like her, the first African-American woman elected to Congress from her state.
“If I waited my turn, I wouldn’t be here,” she said. “There is a gatekeeper mentality that sometimes can diminish new ideas.”
Disenchantment with the policy has moved beyond Washington. A group of college Democrats has organized a boycott of the committee, which has now extended to at least one city council.
“As young Democrats we think this policy will silence our voices,” said Hank Sparks, president of the Harvard College Democrats, which has collected 75 chapters in its boycott, largely symbolic since students are not big donors.
Ms. Pritchard said the policy would have long-term implications for people who work in Democratic politics, too. “I am taking a strong position on something that will change my life,” she said. “People’s livelihoods are being threatened.”