Daniel Goldman

Representative Daniel Goldman, a New York City Democrat fighting to fend off a primary challenge, said on Thursday that he would begin to use his vast personal fortune in an effort to save his House seat.

Mr. Goldman, a Levi Strauss heir and one of the richest members of Congress, put $1 million into his campaign immediately and pledged to begin matching every donation he receives in the run-up to the June primary — a dollar-for-dollar incentive that could cost him millions more.

The congressman framed the decision as a way to show that he was not beholden to special interests. But the cash infusion also underscored just how serious a challenge he faces from Brad Lander, a well-known former city comptroller and mayoral candidate.

There has been little public polling of the race in the 10th Congressional District, which includes Lower Manhattan and a liberal swath of brownstone Brooklyn. Private polling conducted for both campaigns, though, has shown Mr. Lander with a sizable lead in recent weeks, according to three people briefed on it.

Mr. Goldman, whose fortune is valued at as much as $250 million, put almost $5 million into his first race in 2022. But as he seeks his third term, he had hoped to avoid the costs and negative publicity that come with self-funding.

Mr. Goldman said in an interview that his position had changed because of the tone of Mr. Lander’s attacks against him. The challenger’s allies have specifically accused Mr. Goldman of being influenced by the American Israel Public Affairs Committee, the pro-Israel lobby whose members and affiliated groups have supported his campaigns.

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