MANCHESTER, N.H. — Rep. Pramila Jayapal, a rising star in the Democratic Party's liberal wing and one of the most prominent women of color in Congress, is endorsing Sen. Bernie Sanders for president, choosing him over Sen. Elizabeth Warren on the heels of an explosive confrontation over the question of whether a woman can defeat President Trump.

In a telephone interview with The Washington Post on Sunday, Jayapal (D-Wash.) said she decided to endorse Sanders because "he has a clarity on policy prescriptions that goes right to the heart of what working people need." She will unveil her endorsement Monday in Iowa.

"What I feel we need is a candidate who is entirely authentic about what's wrong and steadfast about it and can rally people to believe he can trust them," she said. "Bernie has that. I can feel Bernie beating Trump."

Jayapal also told The Post that she will be named national health policy chair for the Sanders campaign, as well as a Washington state chair.

The endorsement is a significant get for Sanders (I-Vt.) and a blow to Warren (D-Mass.), who has forged a friendship with Jayapal in recent years and is seeking to rally support from women as she makes her closing argument to voters before the first nominating contest in Iowa on Feb. 3.

The backing of Jayapal, who is Indian American and co-chairs the Congressional Progressive Caucus, reflects Sanders’s growing strength on the left and his diversifying coalition. After building a following in 2016 that some saw as too male and too white, Sanders has secured endorsements this time around from barrier-breaking Reps. Alexandria Ocasio-Cortez (D-N.Y.), Ilhan Omar (D-Minn.) and Rashida Tlaib (D-Mich.).

Sanders campaign officials are hoping to deploy Ocasio-Cortez in Iowa in the final stretch of the race there. They have built a busy schedule of events in the early states with a roster of surrogates as Sanders tends to his duties in the Senate as a juror in the Trump impeachment trial.

Jayapal’s support comes days after Sanders secured an endorsement from Rep. Mark Pocan (D-Wis.), the other co-chair of the Congressional Progressive Caucus. The Progressive Caucus is the largest coalition of left-leaning members of Congress. It includes dozens of House members and one senator: Sanders.

Rep. Ro Khanna (D-Calif.), a national co-chair of the Sanders campaign and the first vice chair of the Progressive Caucus, played a leading role in securing the support of Jayapal and Pocan, approaching his colleagues persistently, according to a person with knowledge of the situation. The person spoke on the condition of anonymity to describe private conversations. Khanna also helped secure the endorsement of Ocasio-Cortez.

The Vermont senator spent the weekend campaigning in New Hampshire, where he sought to appeal to female voters and to move past his conflict with Warren. She said in Tuesday’s debate that in a private conversation in late 2018, Sanders disagreed with her assertion that a woman could beat Trump. Sanders forcefully denied saying that.

On a frigid Saturday afternoon in Portsmouth, N.H., Sanders spoke at a women’s march, encouraging men to stand with women on issues affecting them. “We are in this together,” he said. At a town hall in Exeter, N.H., he thanked women for “helping lead the opposition to Trump at every level.”

When asked by a voter in Exeter what his strategy would be as the Democratic field narrows and becomes more prone to infighting, Sanders said he would focus on “issues of the working families of America,” and he blamed the news media, which he said “often wants and exaggerates conflict.”

Yet many Sanders supporters have embraced the chance to battle with Warren, fueling contentious exchanges on social media. Nearly a week after their feud first erupted, the conflict was still raw for supporters of both candidates.

“Up until recently, Elizabeth Warren was my second choice, but she is no longer that,” said Forrest Rapier, a 30-year-old community organizer who felt that when it came to the rift with Sanders, Warren could have “nipped it in the bud.” Rapier, who attended a Sanders rally in Manchester, N.H., said he would write Sanders’s name in on his ballot in the general election if he is not the Democratic nominee.

As Sanders spoke at the women’s march in Portsmouth, Susan Harden, 56, an elementary school teacher from Pelham, N.H., held up a sign urging voters to choose a woman as the nominee against Trump.

“I can understand Elizabeth’s frustration,” she said in an interview, “being called out on the national debate stage.” Harden added, “I think there should be a lot of support for Elizabeth Warren going forward.”

On Saturday, Warren won the endorsement of Janet Petersen, the Democratic leader in the Iowa state Senate.

The disagreement between Sanders and Warren, which played out in Tuesday’s debate, led to an even more heated confrontation afterward, which was captured by CNN microphones. During a brief exchange, Warren accused Sanders of calling her a liar and he replied with the same accusation against her.

In an interview with The Post last summer, Jayapal spoke positively about both Warren and Sanders, recalling fond memories of her first meetings with both candidates. She remembered meeting Sanders in Seattle in fall 2015, during his first run for president. They both spoke at a rally to expand Medicare and Social Security, she said.

“I remember him coming off the stage and he gave me a big hug and said, ‘You said everything I was going to say!’ ” Jayapal said. She said Sanders asked her to introduce him at his evening rally in Seattle. She responded that she would, but told his staff she had not endorsed him yet because she wanted to learn more about his record on race, guns and gender.

The staff promptly set up a meeting, which she said was a positive conversation.

“That happened all in one day,” Jayapal recalled.

She also spoke warmly of Warren, mentioning legislation they have worked on together and the many text messages they have exchanged.

When she ran for Congress in the 2016 cycle, Sanders endorsed Jayapal, which led to a massive fundraising increase, she said in the interview last year.

“A couple days later, I was sitting in the campaign office, and all of a sudden, I started hearing all these — ding, ding, ding — all these sounds,” Jayapal said. “It turned out the staff had the sound on every time a contribution was made. And the computers were just going crazy.” She said she raised $150,000 in 24 hours.

Stein reported from Syracuse, N.Y.