Candidates from the Democratic Party’s left wing held significant leads in three marquee House primaries in New York after Tuesday’s machine ballot count, in a profound show of progressive political power.
One of the contests could lead to the unseating of an entrenched leader: Representative Eliot L. Engel, chairman of the House Foreign Affairs Committee, was badly trailing Jamaal Bowman, an insurgent candidate from Yonkers.
If Mr. Engel, who has served in Congress for more than 30 years, were to lose, it would echo a similar upset in 2018, when Alexandria Ocasio-Cortez defeated Joseph Crowley, then the No. 4 House Democrat.
But this year, the movement seemed to have more reach, as progressive Democrats led the way in contests for two open House seats held by retiring Democrats.
In the Bronx, Ritchie Torres, a city councilman, led a pack of contenders in the 15th Congressional District, where Representative José E. Serrano is retiring. Those trailing Mr. Torres included a political veteran, Rubén Díaz Sr., a conservative former state senator with a history of anti-gay remarks, who had been considered among the favorites.
And in the Hudson Valley district held by Representative Nita Lowey, who is also retiring, Mondaire Jones, a Harvard-educated lawyer, had pulled away from six other candidates in early returns.
Mr. Jones and Mr. Torres would become trailblazers if elected in November: Either would be the first openly gay black member of Congress.
All of Tuesday’s results came with a sizable caveat: State officials had issued nearly two million absentee ballots to voters statewide because of the coronavirus outbreak, and those votes — which could be postmarked as late as Primary Day — would not be fully counted for at least a week.
That means close races may stay in limbo till July. One such close race involves another veteran Democratic incumbent, Representative Carolyn Maloney, who was in a tight race with Suraj Patel, who ran against her in 2018.
Still, early returns seemed to confirm that the liberal wave that elected Ms. Ocasio-Cortez to Congress in 2018 has continued to build momentum.
Ms. Ocasio-Cortez had faced a primary challenge herself but swept it aside easily, even as like-minded candidates — embracing her call for a Green New Deal and Medicaid for All, among other policies — showed electoral muscle.
That strength was perhaps most evident in the 16th Congressional District, which includes parts of the Bronx and Westchester County, and where Mr. Bowman had a hefty lead over Mr. Engel, who was first elected there in 1988.
The race there had illustrated the sharp schism in Democratic ranks, with Mr. Bowman backed by many of the Democrats’ most outspoken progressives and Mr. Engel, fighting for his political life, seeking rescue from more centrist party leaders like Speaker Nancy Pelosi, the former presidential candidate Hillary Clinton, and Gov. Andrew M. Cuomo.
In a speech to supporters on Tuesday night, Mr. Bowman, a middle-school principal, spoke out against poverty, racism and sexism, among other social ills, “a system that’s literally killing us.” He said, if elected, he would be a “black man with power.”
“That is what Donald Trump is afraid of,” said Mr. Bowman, adding: “I cannot wait to get to Congress and cause problems.”
Establishment Democrats could take some solace in easy wins for a number of incumbents, including Representative Gregory Meeks, the chairman of the Queens Democratic Party. Representative Jerrold Nadler, the chairman of the powerful House Judiciary Committee, held a comfortable lead over two challengers, and Representative Yvette Clarke was also leading in her race in Brooklyn, though — as elsewhere — thousands of absentee votes remained to be counted.
Indeed, the sheer number of absentee ballots could prove daunting to election officials, especially considering the battles over vote counts even before the coronavirus, like last year’s contested election for district attorney in Queens. The outbreak caused a number of changes to polling stations, including social distancing, and delays in opening in some locations.