WASHINGTON — The stunning defeat on Tuesday of Representative Joseph Crowley, the fourth-ranking House Democrat and a potential future speaker, threw the future of the septuagenarian-led caucus into chaos, opening the door to a new generation of leadership and a push leftward.
As shock in the capital over Mr. Crowley’s New York primary loss to a 28-year-old first-time candidate, Alexandria Ocasio-Cortez, gave way to calculation, House Democrats began floating challengers to Representative Nancy Pelosi, their leader. The current leadership slate reacted defensively to the threat of a purge, while a handful of other lawmakers braced for their own primary challenges from the left.
Ms. Pelosi dismissed questions about the growing appetite in her ranks for new leaders, and the demand from the party base for more liberal representatives.
“Well, I’m female, I’m progressive — what’s your problem?” she said. “Two out of three ain’t bad.”
But rank-and-file House Democrats made clear in dozens of interviews that whether the party takes back the majority or not in November, there would be a push to depose Ms. Pelosi, the 78-year-old former speaker.
“There will be an insurgency; I just don’t know who’s leading it,” said Representative Emanuel Cleaver II of Missouri. “But I can assure you that I am as certain of that as I am that today is Wednesday.”
The question of who would lead an insurgency offered Ms. Pelosi some reassurance, but it also raised the threat of the unknown. For over a year, she has known that Mr. Crowley or Representative Steny H. Hoyer of Maryland, her 79-year-old second in command and longtime rival, would be her most obvious challengers. Both are white men with roots in the more centrist wing of the party.
Now, though, she could face a race from a colleague who is neither white nor male nor particularly moderate, and that could make it easier for her diversity-minded colleagues to latch on.
House Democrats suggested a host of challengers, including one veteran lawmaker who commands deep respect in the caucus: Representative Elijah E. Cummings of Maryland.
Mr. Cummings said in an interview that he would not challenge Ms. Pelosi, but, notably, he did not bat down the possibility that he would put himself forward should she fail to secure the votes to become speaker or leader.
Representative Cheri Bustos of Illinois, who has made a name for herself urging Democrats to redouble their efforts in the Midwest, also did not deny that she is eyeing a top leadership position.
“I’m open to making sure that I can make a difference in our caucus,” Ms. Bustos said, adding, “And I’ll have some discussions with people about how that may look.”
The sheer range of prospective challengers is remarkable: There are women (Ms. Bustos, Debbie Dingell of Michigan and Karen Bass of California), African-Americans (Mr. Cummings, Ms. Bass and Representatives Cedric L. Richmond of Louisiana and Hakeem Jeffries of New York) and a cadre of younger lawmakers (Representatives Tim Ryan of Ohio, Joseph P. Kennedy III of Massachusetts and Eric Swalwell of California).
Another possibility being discussed on Wednesday was whether Democrats could ease Ms. Pelosi out by installing a transitional caretaker to serve for two years, when the caucus would pick a new leadership team. Mr. Richmond said that if Ms. Pelosi did not have the votes to retain her post, he would support Representative James E. Clyburn of South Carolina, the third-ranking Democrat and a veteran African-American, to be the leader for a term.
“This is like throwing a hand grenade in a fish pond and seeing what comes up,” Representative Rick Larsen, Democrat of Washington, said about the leadership jockeying. Mr. Crowley’s loss, he added, “is making a lot of people accelerate their thinking on the leadership races.”
Lawmakers are, of course, an ambitious bunch by nature. But the vacuum created by Mr. Crowley’s exit seemed to only deepen the yearning for Ms. Pelosi, Mr. Hoyer and Mr. Clyburn to clear the path for a new generation of leaders.
Mr. Clyburn grew testy and admonished a reporter who asked whether he, Ms. Pelosi and Mr. Hoyer could “hold on for life.”
“I hope you would recognize how late in life I got here, and other people who look like me,” said Mr. Clyburn, 77, the highest-ranking African-American in Congress. He added, “I have a set of experiences and I’m not going to take any lecture from you.”
But even some lawmakers who have been supporters of Ms. Pelosi suggested that the caucus must at least consider making a change at the top.
“I think that the party has to weigh all alternatives,” Representative Marcy Kaptur of Ohio, a senior member of the Appropriations Committee, said before predicting that Ms. Pelosi would “hold her own.”
Representative Chellie Pingree of Maine said that she had been proud to back Ms. Pelosi in the past but would not commit to doing so again: “I’m going to keep my powder dry like everybody else.”
But replacing Ms. Pelosi would not be easy. If the party does reclaim the majority, it will be thanks in large part to the votes of women outraged by President Trump. Under those circumstances, it would be difficult for the caucus to dump the first female House speaker in history and replace her with a man.
“It would absolutely be the wrong time to switch out a woman in leadership for a man, unless he brought some other kind of diversity to leadership,” Ms. Pingree said.
Ms. Pelosi is not without her defenders.
“I think Pelosi is very strong within our caucus,” said Representative Jim McGovern of Massachusetts, who is in line to become chairman of the powerful Rules Committee if Democrats take back the House.
In a meeting at the Democratic Congressional Campaign Committee on Wednesday morning, Representative Lois Frankel of Florida complained about those Democratic candidates who were threatening Ms. Pelosi’s future by vowing not to support her, suggesting that the campaign arm should not support them, according to a Democratic official familiar with the conversation.
If Democrats fail to take back the majority, Ms. Pelosi, who has been her party’s leader for over 15 years, would almost certainly be replaced. But if they do capture the chamber, her fate may be determined by just how large their majority is — and whether the freshman lawmakers who pledged to oppose her follow through on their vow.
“These new members are going to expect to be at the table or at least to have their voices represented at the table,” said Mr. Swalwell, 37.
Some of them, like Ms. Ocasio-Cortez, may come to that table having unseated incumbents in primaries.
She has refused to commit to Ms. Pelosi, and a handful of other liberal challengers to sitting Democratic lawmakers have done the same.
In the aftermath of Mr. Crowley’s defeat, many in the caucus turned their attention to the September primary in Massachusetts, where three women are running against veteran House Democrats, each of them white men.
Representative Michael E. Capuano, who represents a minority-majority district in greater Boston, is seen as the most at risk of the three as he confronts a challenge from Ayanna Pressley, a black Boston City Council member who as of April had raised over $363,000.
But Representative Stephen F. Lynch, who is facing a primary from Brianna Wu, a computer programmer, and Representative Richard E. Neal are also hoping to avoid Mr. Crowley’s fate.
“There’s no question that the Trump presidency has roiled political waters everywhere,” said Mr. Neal, who is seeking his 16th term and is facing Tahirah Amatul-Wadud, an African-American lawyer.