Representative Jerrold Nadler, the influential chairman of the House Judiciary Committee, handily defeated his longtime congressional neighbor, Carolyn B. Maloney, in a bruising three-way primary battle on Tuesday that was preordained to end one of the powerful Democrats’ political careers.
The star-crossed skirmish in the heart of Manhattan was unlike any New York City — or the Democratic Party writ large — had seen in recent memory. Though few ideological differences were at stake, it pitted two committee chairs who have served side by side in Washington since the 1990s against each other, and cleaved party faithful into rival factions.
Allies had tried to pull Mr. Nadler off the collision course into a neighboring race after the state’s calamitous redistricting process unexpectedly combined their West and East Side districts this spring. But he pushed forward, relying in a lightning-fast campaign on his reputation as an old-school progressive and leading foil to Donald J. Trump to win over voters in one of the nation’s most liberal districts.
“Here’s the thing: I’m a New Yorker, just like Bella Abzug, Ted Weiss and Bill Fitts Ryan,” Mr. Nadler, 75, told supporters after his victory, referencing liberal lions who represented New York in Congress. “We New Yorkers just don’t know how to surrender.”
Mr. Nadler, in thanking Ms. Maloney, said that the two had “spent much of our adult life working together to better New York and our nation.”
He won the contest for New York’s redrawn 12th District with 56 percent of the vote, compared with Ms. Maloney’s 24 percent, with 93 percent of votes counted. A third candidate, Suraj Patel, earned 19 percent, siphoning crucial votes away from Ms. Maloney, whom he nearly beat two years ago.
It all but assures Mr. Nadler a 16th full term in Congress and Ms. Maloney’s political retirement.
The race — which ended in underhanded jabs about Mr. Nadler’s mental and physical fitness — was the highlight of a string of ugly primary contests that played out across the state on Tuesday, from Long Island to Buffalo, as Democrats and Republicans each fought over rival personalities and the ideological direction of their parties.
In another of the most closely watched contests, Representative Sean Patrick Maloney, the moderate lawmaker tasked with protecting Democrats’ narrow House majority, easily fended off a challenge from Alessandra Biaggi, a state senator and a rising star of New York’s left wing.
The race in the lower Hudson Valley had become an ideological proxy fight, and Ms. Biaggi’s defeat was the latest high-profile setback for leftists in New York. The former President Bill Clinton and House Speaker Nancy Pelosi endorsed Mr. Maloney, while Representative Alexandria Ocasio-Cortez publicly backed Ms. Biaggi.
“Tonight, mainstream won,” Mr. Maloney said in his victory speech. He will face Mike Lawler, a Republican assemblyman, in what may be a competitive general election.
Outside Buffalo, Carl Paladino, a businessman known for his explosive, sometimes racist remarks, was leading a Republican primary against Nick Langworthy, the state Republican chairman who entered the race because he feared that Mr. Paladino could harm the party’s statewide ticket in November.
A 13-candidate Democratic primary in the new 10th District connecting Brooklyn and Lower Manhattan remained too close to call, as did a special election for a Hudson Valley swing seat, vacated by Lt. Gov. Antonio Delgado, that could offer a preview of the general election.
The primary contests were particularly painful for Democrats, who entered the election cycle optimistic that the decennial redistricting process in blue New York would yield crucial pickup opportunities to protect their loose grip on the House of Representatives this fall.
Instead, the state’s highest court ruled this spring that the Democrats’ congressional map was unconstitutional and put in place a neutral alternative. It set off anguishing intraparty brawls that have drained millions of dollars that party leaders had hoped would go toward defeating Republicans and will now cost the state Ms. Maloney’s important House Oversight and Reform Committee chairmanship in Washington.
“It’s a shame,” said Carl Wisotsky, 73, a reliable Democratic voter who was still deciding between Mr. Nadler and Ms. Maloney as he entered a polling station near Lincoln Center on Tuesday. “I’m a Democrat, I’d like the seniority of both these people to remain in Congress.”
Asked what gave Mr. Nadler the edge over Ms. Maloney, he said simply: “West Side over East Side.”
Other New Yorkers struggled mightily to make a distinction between the two lawmakers, who have each racked up overwhelmingly progressive voting records, become synonymous with their respective geographic bases and often counted on the same unions and political leaders to support them.
For Ms. Maloney, 76, the defeat is likely to spell a painful end to a pathbreaking career in elected office. A former teacher and legislative aide, she first won a seat on the City Council from East Harlem in 1982 and a seat in Congress representing the East Side’s famed “Silk Stocking” district a decade later, eventually rising to become the first woman to lead the Oversight Committee.
“I’m really saddened that we no longer have a woman representing Manhattan in Congress,” Ms. Maloney said in a concession speech. “We cannot and we must not give up. The fight continues.”
In the shadow of the Supreme Court’s decision to overturn Roe v. Wade, Ms. Maloney campaigned aggressively on her record of fighting for feminist causes. She pointedly accused Mr. Nadler of trying to take credit for her legislative priorities, like the Second Avenue Subway, and ran a television ad for weeks telling New Yorkers, “You cannot send a man to do a woman’s job.”
As she veered toward defeat in recent days, her approach took an uglier turn, with allies and the congresswoman herself fanning questions about Mr. Nadler’s physical health, mental acuity and determination to serve a full term. (“That’s ridiculous obviously,” he said, dismissing them as “desperation tactics.”)
Mr. Patel, 38, tried to make the race about generational change, arguing that the Democratic Party needed “to change the vibes” with fresh leaders rather than failed “1990s politicians” like Mr. Nadler and Ms. Maloney.
Neither frame ultimately proved persuasive to voters, though, or at least not enough to overcome the enthusiastic base of support that turned out for Mr. Nadler on the Upper West Side in the face of the unusual timing of the election in late August.
Despite having not faced a serious challenge in decades, Mr. Nadler quietly managed to assemble an enviable roster of endorsements, while casting himself as a consistent warrior for civil rights and civil liberties whose experience was needed as the former president and his acolytes shake some of the foundations of American government.
As the race stretched on, he also went on the attack against Ms. Maloney, accusing her of poor judgment when she voted for the Iraq War (he voted against) and when she helped amplify questions about debunked ties between vaccines for children and autism. A shadowy super PAC that has yet to disclose its donors picked up on the attack and spent more than $200,000 on television ads driving it home.
But above all, Mr. Nadler played a deft inside game, calling on decades-long relationships to build a stable of powerful supporters, including Senator Elizabeth Warren of Massachusetts, New York’s Working Families Party and Senator Chuck Schumer of New York, the majority leader, who was the only member of the state’s congressional delegation to wade into the race.
Still, with his advancing age and noticeably halting debate performances, questions are likely to accelerate about who might succeed him.
Other Democratic struggles were just as toxic, but generated less wattage than the Nadler-Maloney contest.
In the neighboring 10th District, Daniel S. Goldman, a wealthy former federal prosecutor and MSNBC commentator who helped build an impeachment case against Donald J. Trump, declared victory with a slight lead over Yuh-Line Niou, a Manhattan assemblywoman backed by the Working Families Party. They were ahead of Carlina Rivera, a Manhattan councilwoman, and Representative Mondaire Jones, a first-term progressive who moved to Brooklyn this summer after his current district, in Rockland and Westchester Counties, was reshuffled.
“While we appreciate and respect the democratic process and will wait until all the votes have been counted, it is quite clear from the way the results have come in that we have won,” Mr. Goldman said.
Ms. Niou, in her own remarks, hinted at the coming result but said she was not ready to concede.
Mr. Goldman, a Levi Strauss heir, became a common target in the closing weeks. His opponents accused him of trying to buy the seat by plowing nearly $5 million of his personal fortune into the race and of being insufficiently liberal on issues like abortion, based on comments he said he mistakenly made in a media interview. But with so many candidates in the race with broadly similar positions, the left wing remained fractured, and Mr. Goldman’s financial advantage and track record of taking on Mr. Trump seemed to help distinguish him.
Results were similarly close in the special election for the Hudson Valley swing seat, as counting continued. Both parties were looking to the race for a preview of this fall’s midterm contests: The Democrat, Pat Ryan, sought to make it a referendum on abortion rights after the Supreme Court’s decision overturning Roe v. Wade, while his Republican opponent, Marc Molinaro, has remained tightly focused on New York’s fast-rising living costs.
The winner will serve in Washington for the remainder of the year, but both candidates will be running again this fall in separate, newly drawn districts.
Téa Kvetenadze and Sean Piccoli contributed reporting.