Representative Diana DeGette of Colorado said on Wednesday that she would challenge Mr. Clyburn, but she is not expected to topple him, particularly given his base of support in the Black Caucus. Ms. DeGette, who has been the chief deputy whip for more than a decade, said in an interview that she did not “intend to have a messy leadership race.”
Representative Ben Ray Luján of New Mexico, the triumphant chairman of the Democratic Congressional Campaign Committee, announced on Wednesday that he would seek the post of assistant majority leader, the No. 4 job, which is already being pursued by David Cicilline of Rhode Island and Cheri Bustos of Illinois.
Republicans were also grappling for power. Representative Jim Jordan of Ohio, the founder of the hard-right Freedom Caucus, announced that he would seek the post of minority leader, pitting him against Representative Kevin McCarthy of California, the current No. 2 Republican.
In an interview with The Hill on Wednesday, Mr. Jordan placed the blame for Republican losses in the House at the feet of the leaders, suggesting they had not been conservative enough or sufficiently willing to bulldoze Democratic opposition to muscle through Mr. Trump’s top priorities such as repealing the Affordable Care Act, building a huge border wall or cutting welfare. He spent Wednesday dialing fellow Republicans to make his case.
Mr. McCarthy defended his tenure, telling House Republicans in a letter that the party had enjoyed “great gains,” including tax cuts and a reduction in federal regulations.
Representative Steve Scalise of Louisiana said he would run for whip, the No. 2 spot, ending speculation that he might challenge Mr. McCarthy. Representative Liz Cheney of Wyoming announced she would seek the job of Republican conference chairwoman, setting up a likely showdown with the current chairwoman, Representative Cathy McMorris-Rodgers of Washington.
The maneuvering among top Democrats was quieter. Mr. Hoyer has begun collecting signatures from allies for a letter highlighting his experience, his ability to take on Mr. Trump, and the steps he has taken to advance younger members on his whip team, according to two Democrats familiar with the effort.