SHRUB OAK, N.Y. — Less than three months before the November midterm elections, the man tasked with protecting the imperiled Democratic House majority was contemplating a more immediate challenge: securing his own political survival in a primary contest this week.

“How am I doing on the vote?” Representative Sean Patrick Maloney of New York asked a voter as he worked a barbecue here last Wednesday afternoon, dousing a hot dog in mustard and relish and commiserating with older attendees about impatiently awaiting the birth of grandchildren.

“I see your commercial every 10 seconds,” the voter told him.

New York’s tumultuous primary season, which draws to a close on Tuesday, has no shortage of hard-fought, high-drama contests. But because of Mr. Maloney’s standing as the chair of the House Democratic campaign arm — and given the cast of prominent politicians who have gotten involved in the race — perhaps no New York primary is of greater national consequence than the battle for the newly redrawn 17th District, which includes parts of Westchester County and the Hudson Valley.

By every standard metric — fund-raising, television presence, available polling, endorsements and the assessments of several local elected officials — Mr. Maloney heads into Primary Day with a strong advantage. But New Yorkers are unaccustomed to voting in August, and low-turnout elections can be especially unpredictable.

On the ground, it is apparent that a contested race shaped by ideological, generational and stylistic tensions is underway. The winner is expected to face a competitive general election challenge from emboldened Republicans this fall.

“Maloney might be more of my choice just because I’m a fan of Bill’s,” said Tim Duch, 71, referencing the former president whose Chappaqua home is in the new district (Hillary Clinton, who helped lead Ms. Biaggi’s wedding ceremony, has stayed on the sidelines). Nodding to Mr. Clinton’s comment that Mr. Maloney has won competitive races, he added, “I think that’s what Bill Clinton was saying, that he’s more winnable.”

Mr. Duch was standing outside a bookstore on Tarrytown’s cafe-lined Main Street with his wife, Lee Eiferman, on Wednesday morning when Ms. Biaggi walked by.

“Energy,” Ms. Eiferman, 68, observed after Ms. Biaggi greeted them effusively. Referencing criticism she had heard about Ms. Biaggi concerning her law enforcement stance, Ms. Eiferman added: “She’s for women’s issues, and everything that she’s getting shish-kebabbed on, I’d say bring it on.”

The contours of the race were set in motion after a messy redistricting process this spring that split Mr. Maloney’s current district in two. Instead of running for a reconfigured version of his current seat, Mr. Maloney opted to contest a slightly more Democratic-leaning district now represented by a Black Democrat, Mondaire Jones, who aligns with the party’s progressive wing.

Though Mr. Maloney noted that his Cold Spring home was within the new lines, it set off a nasty brawl. Furious colleagues cast it as a power grab, and Mr. Jones ended up packing his bags for New York City, where sparse public polling now shows him trailing in a race for an open House seat there.

Mr. Maloney has acknowledged that he could have handled the process better, and a number of lawmakers who sharply criticized him at the time no longer appear interested in discussing the subject.

But Mr. Maloney, 56, has long been regarded as an ambitious political operator, and some hard feelings remain.

National tensions were compounded when the Democratic Congressional Campaign Committee elevated a far-right candidate in a Republican primary in Michigan, a move that was sharply criticized by many as hypocritical and dangerous. (Mr. Maloney has defended it by noting his party’s improved prospects in the general election there.)

Ms. Biaggi, 36, has seized on both dynamics to lash Mr. Maloney as a notably self-interested politician who does not grasp the urgency of the moment.

“He’s a corporate Democrat with no integrity — let me actually, let me amend that — he’s a selfish corporate Democrat with no integrity,” she said over coffee in Tarrytown, not far from her new home in North Castle (she grew up in Westchester but recently moved to the newly configured district). “He’s not really thinking about the broader team.”

Voters, she said, want a fighter whose first instinct in the wake of seismic events like the overturning of Roe v. Wade is not to send fund-raising emails — a criticism leveled by other Democrats who thought the party was ill-prepared to respond after the Supreme Court’s decision.

“The person who can make the strongest case is the person who doesn’t embody everything that people hate about politics,” she said, referring to the candidates’ general election prospects. Both of them talk about how best to engage working people.

Mr. Maloney, for his part, also says that he is a pragmatic, “hometown guy” with a record of delivering for the region while managing his D.C.C.C. duties, noting the committee’s fund-raising efforts and the signs of an improving political environment. He attended a major donor retreat in Napa County, Calif., this weekend to raise money for House Democrats, a D.C.C.C. spokesman confirmed.

In an interview in which he repeatedly muttered about his disdain for Twitter, the congressman dismissed Ms. Biaggi’s criticism as “desperate rhetoric” and the hallmark of a “failing” campaign that he suggested was out of step with what will be a politically competitive district in November.

“If you look around the country, I think what’s clear is that the common-sense wing of the Democratic Party that is focused on working with people to get things done is on the rise, and the socialist wing is on the decline and it’s about time,” he said.

Asked if he considered Ms. Biaggi part of the “socialist wing” of the party, Mr. Maloney cited her past criticism of law enforcement as “absolutely outside the mainstream.” Ms. Biaggi does not identify as a democratic socialist and has stopped using the phrase “defund the police.”

Some of her past remarks have become an issue in the campaign anyway, particularly as outside money has poured in against her from groups including the Police Benevolent Association of the City of New York, which endorsed former President Donald J. Trump in 2020.

Inara de Leon, a former TV news producer from Chappaqua, said she was aware of the knocks against Mr. Maloney — but they paled next to her concerns about some of Ms. Biaggi’s progressive views and her confrontational style. She specifically cited a mailer she had received amplifying a Twitter post Ms. Biaggi wrote in July asking, “When a majority of Congress is past childbearing age, how fierce can we expect their fight to be?”

“I’ve had children, and I know I’m just as feisty now as I was then,” said Ms. de Leon, 71. “I’m not sure I want to add another person like that to that end of the Democratic Party.”

Ms. Biaggi, a granddaughter of the late congressman Mario Biaggi, has emerged as a state leader of the progressive movement. But after spending months running in a different part of the region before the redistricting shuffle, she has had limited time to introduce herself to voters.

Even some Democrats who vocally championed her entry into the primary have turned their attention elsewhere: A spokeswoman for Representative Jamaal Bowman, Democrat of New York, declined to comment on the story and said he was focused on his own race.

Ms. Biaggi said she was “organizing the heck” out of the district. She has not aired ads on television but has pursued an active mail program. Both campaigns claim extensive direct voter contact efforts.

As for the tweet Ms. de Leon cited, Ms. Biaggi said that it was referencing “the fact that the generation above us has been in office for a long time. They have failed at the federal level to protect abortion rights. And when Roe was overturned, they sent fund-raising emails. No urgency.”

On the ground, there are signs of generational divisions.

“I’m inspired by her energy,” said Emily Marsh, 32, of Cold Spring. “It’s really cool that she’s around my age.”

Mr. Maloney used his time in the district on Wednesday to herald the legislative momentum Democrats are now enjoying. He held an event touting the climate, tax and health care package that President Biden recently signed into law. And at the barbecue, he discussed with older voters how the measure would affect prescription drug costs for seniors on Medicare.

“Seniors is the most important thing,” said Billie Desisto, 81, in a Bronx accent. “If Maloney takes care of us, we take care of him.”