A new trio, including Representatives Katherine Clark of Massachusetts as No. 2 and Pete Aguilar of California as No. 3, will take the reins in January, replacing Speaker Nancy Pelosi and her team.Representative Hakeem Jeffries, Democrat of New York, will become the minority leader in January after Speaker Nancy Pelosi, who has led the Democrats for two decades, announced that she would step aside.Haiyun Jiang/The New York TimesWASHINGTON — House Democrats on Wednesday elected a new generation of leaders to take the mantle from the three octogenarians who have led them for two decades, installing a trio of top leaders that, for the first time in congressional history, includes no white men.In a display of unity after midterm elections in which they lost the House but had a stronger than expected showing, Democrats skipped a vote and by acclamation elected Representative Hakeem Jeffries of New York to be minority leader, making him the first Black person to claim the top spot. Representative Katherine Clark of Massachusetts was elected as whip, the lead vote counter for House Democrats, and Representative Pete Aguilar of California as the chairman of the party caucus, in charge of messaging.Mr. Jeffries, 52, Ms. Clark, 59, and Mr. Aguilar, 43, who for years have positioned themselves as an unofficial joint slate and patiently waited their turn, ran unopposed after Speaker Nancy Pelosi, the California Democrat who has led the party for two decades, announced after the midterm elections that she would step aside, paving the way for fresher faces at the top of her party.Representative Steny H. Hoyer of Maryland, the majority leader, had considered trying to remain in leadership and said he had the support to do so, but ultimately decided against it. And Representative Adam B. Schiff of California had considered a challenge to Mr. Jeffries for the post of minority leader, but many Democrats said he lacked the votes. Last week, Mr. Schiff told Mr. Jeffries that he was instead exploring a run for Senate and wished the representative well in the upcoming leadership election, according to a person familiar with the private conversation who disclosed it on the condition of anonymity.The mood was jubilant on Wednesday inside the ornate committee hearing room across from the Capitol where Democrats met to elect their new leaders.“We want Petey Pie!” lawmakers chanted as they nominated Mr. Aguilar, using a nickname his grandmother gave him, according to two people in the room.At another point, Representative Terri Sewell of Alabama led a call-and-response chant for Mr. Jeffries, borrowing a lyric from the rapper Biggie Smalls, whom Mr. Jeffries famously quoted on the Senate floor during former President Donald J. Trump’s first impeachment trial.A New U.S. Congress Takes ShapeFollowing the 2022 midterm elections, Democrats maintained control of the Senate while Republicans flipped the House.Divided Government: What does a split Congress mean for the next two years? Most likely a gridlock that could lead to government shutdowns and economic turmoil.Democratic Leadership: House Democrats elected Hakeem Jeffries as their next leader, ushering in a generational shift that includes women and people of color in all the top posts for the first time.G.O.P. Leadership: After a midterms letdown, Representative Kevin McCarthy and Senator Mitch McConnell faced threats to their power from an emboldened right flank.Ready for Battle: An initiative by progressive groups called Courage for America is rolling out a coordinated effort to counter the new Republican House majority and expected investigations of the Biden administration.“If you don’t know,” Ms. Sewell shouted out, “Now you know,” the members called back.Afterward, Mr. Jeffries nodded to the historic nature of his election, saying, “I stand on the shoulders of Shirley Chisholm and others,” a reference to the former representative from his district who in 1968 became the first Black woman to be elected to Congress.Democrats, for the most part, said they saw the lack of competitive races as a sign of strength and unity, and a stark contrast to the fractured Republican conference.Representative Kevin McCarthy, the Republican leader, is struggling to win the support he needs to become speaker amid a revolt on his right flank. A historically weak midterm performance has handed the G.O.P. a thin House majority for the next Congress, making the job of leading it exceedingly difficult.Representative Katherine Clark of Massachusetts was elected as whip, the lead vote counter for House Democrats.Haiyun Jiang/The New York Times“It shows that Democrats are in array, Republicans are in disarray,” said Representative Ted Lieu of California, noting that the new slate of leaders, which includes a Black man, a white woman and a Latino man, “reflects the beautiful diversity of America.” Mr. Lieu, later on Wednesday, won election to be the vice chairman of the Democratic caucus, putting him in line to become the first Asian American to hold that post.Representative Ilhan Omar of Minnesota said she was excited to have a leader in Mr. Jeffries “who actually does represent the diversity of our caucus.”In a news conference after the top three jobs were cemented, Mr. Aguilar said that the election showed that “while Kevin McCarthy is auctioning off real estate and square footage for every vote he can, we’re united together.”Mr. Jeffries said House Democrats held together because they shared a commitment to fighting for “young people, seniors, immigrants, veterans, the poor, the sick, the afflicted, the least, the lost and the left behind.”From the minority in the House, he said Democrats would “push back against extremism whenever necessary.”Yet some Democrats called the uncontested election a missed opportunity to discuss how their party was shifting and how it should move forward.“This is the most significant generational change that we have seen in House Democrats in several decades,” said Representative Alexandria Ocasio-Cortez of New York. “I personally believe that we would benefit from a debate on what that means.”The leadership elections marked a sea change for the caucus, which for two decades has been led by the same three leaders, who effectively froze out dozens of more junior lawmakers who had been waiting to ascend.Ms. Pelosi’s announcement before Thanksgiving that she would step down from leadership set the long-awaited change in motion. Mr. Hoyer quickly followed suit and Representative James Clyburn of South Carolina, the whip, said he would relinquish the third-ranking spot and seek a lower position.His decision to stay in leadership, however, rankled some members.On Wednesday, Representative David Cicilline of Rhode Island, who is gay, said he planned to challenge Mr. Clyburn for the position of assistant leader.“With so much at stake, I think it is critical that the House Democratic leadership team fully reflect the diversity of our caucus and the American people by including an L.G.B.T.Q.+ member at the leadership table,” he said in a letter to his colleagues announcing his bid. That race will be decided on Thursday.Representative Pete Aguilar of California as the chairman of the party caucus, in charge of messaging.Haiyun Jiang/The New York TimesIn remarks to reporters ahead of the election, Mr. Jeffries described the role he was about to assume as a “solemn responsibility.”“When we get an opportunity as diverse leaders to serve in positions of consequence, the most meaningful thing that we can do in that space is do an incredibly good job,” Mr. Jeffries said.He downplayed the divisions among Democrats and expressed confidence in his ability, along with his expected leadership team, to keep the party united in the coming year.“There’s nothing more unifying than being in the minority and having a cleareyed objective and goal of getting back into the majority so we can continue to deliver big things for everyday Americans,” he said.Senator Chuck Schumer, the majority leader, said he had known Mr. Jeffries, a Brooklyn neighbor, for years and expected to speak with him the same amount he now talks with Ms. Pelosi: about four to five times a day.“It’s a little like Pelosi,” Mr. Schumer said in an interview. “When I first met her, I said, ‘This person is special, she’s going somewhere.’ I felt the same way about Hakeem.”Mr. Schumer said Mr. Jeffries “always had the leg up” in the race to succeed Ms. Pelosi.“He’s very good at reaching out to people of many ideologies,” Mr. Schumer said, predicting that Mr. Jeffries would be able to reach across party lines.“There’s going to be a whole bunch of Republicans who are not going to be happy with the MAGA direction of the party, and I couldn’t think of a better person to work with them to try and get some things done,” Mr. Schumer said.Luke Broadwater More