For decades, Ronald S. Lauder, the billionaire cosmetics heir and philanthropist, has been something like a one-man bank for Republicans in New York.

He personally funded a campaign to impose term limits in New York City, helped pay for a lawsuit to overturn the state’s gerrymandered congressional map and, just four years ago, plowed close to $13 million into races that helped Republicans flip the House.

Now, in the middle of another crucial midterm election year, Mr. Lauder, 82, appears to have abruptly closed his political checkbook, and the ramifications for the conservative movement he has nurtured in his home state could be significant.

He has yet to make a single donation to Republicans in his home state this year, according to campaign finance records. The super PAC he long maintained to advance Republican candidates and causes is also sitting idle.

And behind the scenes, Mr. Lauder has quietly dismissed a stable of well-paid advisers, ad makers and other consultants who regularly reported to his personal office in the Estée Lauder headquarters overlooking Central Park in Manhattan. Some had been with Mr. Lauder since 1989 when he ran his own quixotic race for mayor.

His motivation is not entirely clear. Three associates said that Mr. Lauder recently confided in them, saying that his adult children have stepped in to try to reduce his lavish spending on politics, art and philanthropy and suggesting reluctantly that he could not spend what he once did. The associates pointed to public securities filings showing that his stake in the family business, Estée Lauder, has lost at least $1.2 billion in value as the stock plummeted 77 percent from its 2021 high.

A person close to the Lauder family did not dispute that Mr. Lauder’s political spending was being curtailed, but said it was not because of a financial pinch.

Rather, the person said that he and his adult children had agreed that he would simplify the reach of his activities — involving extensive travel, large paid staff and public speeches — as he prepared for the last years of his life in order to prioritize art and philanthropic projects that could secure his legacy.

The New York Times pieced together this account of one of New York City’s most publicly engaged donors and philanthropists by examining public campaign finance records and corporate disclosures by Estée Lauder, and interviewing more than a dozen of his associates. Most insisted on anonymity to avoid crossing him.

Mr. Lauder himself did not respond to a detailed list of questions from The Times about his financial position or decision making. In a written statement, he said that he had used political giving and philanthropy over the years to “strengthen” the city, adding, “I intend to continue dedicating my time, resources and energy to advancing those democratic principles and to ensuring that New York remains a place where people, families, businesses and communities can thrive.”

Some Republicans are holding out hope that Mr. Lauder might still involve himself in this year’s races. But Gerard Kassar, the chairman of the New York Conservative Party, said he had been advised by Allen Roth, a longtime Lauder lieutenant who recently left, that the billionaire “got to a certain age that his family and him all decided he wasn’t going to be as active the way he has been.”

Mr. Kassar said he did not know anything about Mr. Lauder’s personal finances, but was led to believe he would no longer be a major funder.

“Can anyone replace him in New York financially?” Mr. Kassar said. “The simple answer is no.”

Edward F. Cox, Mr. Kassar’s counterpart at the state Republican Party and a longtime friend of the Lauder family, declined to comment.

There is little doubt that Mr. Lauder is still enormously wealthy. He owns one of the world’s most respected private art collections, a Gulfstream with custom Hermès interiors and compounds in Palm Beach and the Hamptons. Forbes estimates that he and both of his adult daughters are worth billions of dollars.

There are signs that Mr. Lauder is taking other significant actions that could reverberate far beyond the political world. Many of the maneuvers, including giving up his Estée Lauder board seat, are consistent with the kind of estate planning typical of a wealthy person of his age.

But some of the moves he initiated over the past few years have also either generated substantial cash or offloaded tens of millions of dollars in future obligations at a time when the family business had taken a sharp downward turn.

In the most high-profile case, Mr. Lauder announced in May that his beloved Neue Galerie, the Upper East Side museum he founded to showcase the culture of prewar Austria and Germany, would be merging with the Metropolitan Museum of Art.

Both sides framed the blockbuster merger as a way to preserve the museum well beyond Mr. Lauder’s lifetime and strengthen the Met’s collection. But it would also be likely to save Mr. Lauder millions of dollars a year that he contributes to covering its operating expenses, according to the organization’s financial disclosures.

Mr. Lauder also recently announced that he would leave the presidency of the World Jewish Congress, an international federation of Jewish groups, where he has been the major funder and leader for two decades.

At the same time, Mr. Lauder, who began collecting as a teenager — real estate, planes and, most of all, art — has quietly been selling at a notable clip.

In late 2023, as the Estée Lauder stock slide accelerated, he sold a Philip Johnson-designed home in Manhattan for $20 million in an off-market deal. In late 2024, he sold 30 acres of land to the Town of East Hampton’s preservation fund for $56 million, and put his collection of World War II fighter planes on the market, according to an aviation enthusiasts’ website.

Mr. Lauder’s retrenchment has played out at a time of significant change for his storied family. His older brother, the businessman and philanthropist Leonard A. Lauder, died last year. His son-in-law, Kevin M. Warsh, was recently nominated to the chairmanship of the Federal Reserve by President Trump, a longtime friend of Ronald Lauder.

While Leonard Lauder spent his career leading the family business, Ronald Lauder carved out a path as an independent investor, philanthropist, art collector and political player, serving as a U.S. ambassador under Ronald Reagan.

Those pursuits were expensive, and in addition to outright selling his stock, Mr. Lauder long made a practice of using shares in the family business as collateral for bank loans and other financial transactions to help fund it all. (Estée Lauder’s most recent annual federal securities filing disclosed that he had pledged nearly all his remaining shares to a bank.)

The maneuver is popular among people who derive their wealth from stocks as a way to generate cash from their holdings without selling them and paying taxes. It would have had little downside when the company’s stock was going up in value. Estée Lauder shares peaked, at the end of 2021, at around $370 a share.

But there can be risks if the stock used as collateral loses considerable value. If the assets’ values fall far enough, a lender may ask the borrower to repay part of the loan or pledge more assets to maintain it.

The terms of Mr. Lauder’s borrowing are not specified in the Estée Lauder disclosures. As of this week, the stock was trading at around $85 a share.

The person close to the Lauder family conceded that the stock price’s slide could limit Mr. Lauder’s overall capital, but asserted that he did not have a meaningful liquidity problem. (The person declined to share financial records that would substantiate the claim.)

Mr. Lauder’s political giving has been relatively less expensive than his other pursuits. (He once spent $135 million on a single Gustav Klimt painting, which became the centerpiece of the Neue Galerie.) Over the last decade, public records show he has spent more than $40 million on state and federal races.

But in New York, he developed a reputation as a singular donor engaged not just in backing candidates but in embracing causes with outsize impact. In the 1990s, Mr. Lauder bankrolled a campaign that won term limits for public officials in New York City. In the 2010s, he was instrumental in stopping Mayor Bill de Blasio’s push to change the admissions test for city’s specialized public high schools.

As recently as last year, Mr. Lauder was spending aggressively on politics. He gave $5 million to MAGA Inc., a super PAC backed by President Trump, in March 2025. (Mr. Lauder has gotten credit for giving Mr. Trump the idea to buy Greenland.) He donated another $1 million to a super PAC opposed to Zohran Mamdani’s mayoral campaign.

His free-spending ways caused Leonard Lauder to once say to an admirer who had confused him with his brother: “I’m the one who made the money. He is the one who spends the money.”

But the political contributions came to an abrupt stop at the beginning of this year, just as Bruce Blakeman, the Republican nominee for governor in New York, needed his help trying to narrow Gov. Kathy Hochul’s fund-raising advantage.

Mr. Lauder could theoretically decide to restart his giving. His decision to cull his longtime political staff was more lasting, and one that he indicated to associates he was not eager to make.

While it is difficult to independently determine the full cost of his personal office, Estée Lauder securities filings give some hints.

Mr. Lauder long had an arrangement with the company to house his personal office in the company’s Midtown headquarters. As part of the deal, Estée Lauder would provide some services, like payroll and phone systems, and Mr. Lauder would reimburse. The cost during the 2025 fiscal year, the filings show, was nearly $22 million.

As Mr. Lauder was cutting staff this spring, his chief financial officer sent an email that made it clear that the billionaire was facing new constraints even in his own office.

“Please note that if you are asked by Mr. Lauder or anyone else on his behalf to perform future work you must get my prior written approval,” the chief financial officer, Joseph F. Tuite Jr., wrote in the email, reviewed by The Times. “Should you perform services without this written approval, you will not be paid.”

Zachary Small contributed reporting.