For months, the Democratic contest on eastern Long Island to choose a candidate most capable of unseating Representative Nick LaLota, the Republican incumbent, has been cordial, if not overly polite.
Debates between the two Democratic candidates, John Avlon and Nancy Goroff, have focused on bigger-picture national issues, such as abortion, as well as local concerns, like the rising cost of living, with neither of them pursuing a scorched-earth strategy.
But in the final days before the primary on June 25, the tenor has started to change.
Ms. Goroff, who has contributed $1.2 million to her campaign, has run a string of attacks against Mr. Avlon in recent weeks. Mailers have featured images of a laughing Rudolph W. Giuliani — whom Mr. Avlon worked for as a policy adviser and a speechwriter — perched on Mr. Avlon’s shoulder, while television ads have accused him of supporting Republican efforts to slash Medicare benefits, and have said that he ran a “dark money group.”
Ms. Goroff, a retired chemistry professor who ran unsuccessfully for the seat in 2020, seemed like the prohibitive favorite until Mr. Avlon, a former CNN political analyst and a former editor of The Daily Beast, made a late entrance to the race in February.
They are now the last two Democrats standing in what began as a crowded field, with Jim Gaughran, a former state senator, and Kyle Hill, a former congressional aide, initially also seeking the nomination.
The winner will face Mr. LaLota, a first-term Republican who succeeded Lee Zeldin after he left the post to run for governor in 2022. The Democratic House Majority PAC has characterized the race as “one of the most competitive districts in the country,” while the Cook Political Report has called it “likely Republican.”
Mr. Avlon, who helped found the centrist political group No Labels, is a recent arrival in the district, and his detractors have painted him as a Manhattan dweller with a vacation house in the Hamptons.
Mr. Avlon and his wife, Margaret Hoover, a conservative host on PBS, bought a home in Sag Harbor in 2017, and Mr. Avlon voted in the district for the first time in 2020, according to voting records. Ms. Goroff, in contrast, taught in the district, at Stony Brook University, for 20 years, and she raised her two children in Suffolk County, according to her campaign website.
Despite his apparent lack of local ties, Mr. Avlon has quickly shored up support in the district, garnering 29 individual endorsements from party leaders and local elected officials like Representative Tom Suozzi, who recently won a special election in the neighboring Third Congressional District. Ms. Goroff has 15 individual endorsements, including from four current members of Congress, and she has six endorsements from political groups such as Emily’s List.
Democratic leaders have voiced concern that Ms. Goroff’s attacks against Mr. Avlon will weaken whichever candidate emerges to face what will be an uphill battle against Mr. LaLota in November. In 2020, President Biden won the district by 0.2 percentage points, while Ms. Goroff lost to Mr. Zeldin by 10 points.
“When Democrats in a primary resort to attacking other Democrats solely in the hope of winning that primary but with no care to the consequences if they do not, they lay bare the selfishness that motivates them — which is unbecoming to public service,” Jay S. Jacobs, the chair of the New York State Democratic Committee who has endorsed Mr. Avlon, said of Ms. Goroff’s tactics.