She was an heiress without a cause — an indifferent student, an unhappy young bride, a miscast socialite. Her most enduring passion was for birds.

But Cordelia Scaife May eventually found her life’s purpose: curbing what she perceived as the lethal threat of overpopulation by trying to shut America’s doors to immigrants.

She believed that the United States was “being invaded on all fronts” by foreigners, who “breed like hamsters” and exhaust natural resources. She thought that the border with Mexico should be sealed and that abortions on demand would contain the swelling masses in developing countries.

An heiress to the Mellon banking and industrial fortune with a half-billion dollars at her disposal, May helped create what would become the modern anti-immigration movement. She bankrolled the founding and operation of the nation’s three largest restrictionist groups — the Federation for American Immigration Reform, NumbersUSA and the Center for Immigration Studies — as well as dozens of smaller ones, including some that have promulgated white nationalist views.

Today, 14 years after May’s death, her money remains the lifeblood of the movement, through her Colcom Foundation. It has poured $180 million into a network of groups that spent decades agitating for policies now pursued by President Donald Trump: militarizing the border, capping legal immigration, prioritizing skills over family ties for entry and reducing access to public benefits for migrants, as in the new rule issued just this week by the administration.

“She would have fit in very fine in the current White House,” said George Zeidenstein, whose mainstream population-control group May supported before she shifted to anti-immigration advocacy. “She would have found a sympathetic ear with the present occupant.”

While her unlikely role as the quiet bursar to anti-immigration organizations has been previously reported, May’s motivation and engagement in the immigration issue remained largely hidden.

The New York Times, through dozens of interviews and searches of court records, government filings and archives across the country, has unearthed the most complete record of her thinking. May’s unpublished writings reveal her evolution from an environmental-minded Theodore Roosevelt Republican to an ardent nativist.

Chatty, handwritten notes to John D. Rockefeller III, philanthropist Helen Clay Frick and the head of the National Audubon Society about luncheons and overseas trips gradually gave way over the years to darker exchanges with fringe figures who believed that black people were less intelligent than white people, Latino immigrants were criminals and white Americans were being displaced.

But May disputed the notion that she was racist, writing to a grant recipient in November 1994, “Can we not put imaginary paper bags over the immigrants’ heads, see them as colorless consumers, and count only their deleterious numbers?”

Restrictionist groups she financed have blocked attempts at amnesties and immigration reform bills in Congress over the years. They fought for Proposition 187 in California to deny education, routine health care and other public services to immigrants in the country without permission; they argued against in-state tuition for the children of undocumented workers in Utah. They supported “show me your papers” laws in Arizona and Georgia and draconian local ordinances in Hazleton, Pennsylvania, and Farmers Branch, Texas.

“We occupied the space before anybody, and the people who helped found the organization and fund the organization, including Mrs. May, were people of enormous foresight and wisdom,” said Dan Stein, president of the Federation for American Immigration Reform, who knew May. “They would be gratified over the fact that we’ve seen these ideas championed at the highest level.”

The groups have wasted little time seizing the moment since Trump came to the White House. As Stein’s organization, known as FAIR, put it in a federal tax filing last year, Trump’s election presented “a unique opportunity” to enact its long-standing agenda of “building the wall, ending chain migration, rolling back dangerous sanctuary policies, eliminating the visa lottery” and more.

Nowhere in the document is the name of its largest benefactor ever mentioned.

“Without Cordy May, there’s no FAIR,” said Roger Conner, the organization’s first executive director. “There was no money without her.”

— Two Passions Converge

After a marriage at age 20 that lasted just a few months, May joined in the family tradition of philanthropy. But it was Margaret Sanger, the famous and, in some circles, scandalous founder of Planned Parenthood, who provided the sense of direction May had craved.

May first worked for the Planned Parenthood chapter in Pittsburgh and later joined the board of the International Planned Parenthood Federation. “I have always admired and tried to take a part in the work that you started,” she wrote in a 1961 letter to Sanger.

May appeared to live relatively modestly, considering her means, but she kept a private jet nearby and flew around the world on nature expeditions. She was more comfortable banding birds at a wildlife sanctuary than hobnobbing at a cocktail party.

Her twin passions, protecting natural habitats and helping women prevent unplanned pregnancies, merged over time into a single goal of preserving the environment by discouraging offspring altogether. “The unwanted child is not the problem,” she would later write, “but, rather, the wanted one that society, for diverse cultural reasons, demands.”

May joined the board of the Population Council, a group founded by John D. Rockefeller III that emphasized family planning and economic development as ways to lower birthrates around the world. She and some relatives together contributed $11.4 million to the council during the 1960s, and May joined the group’s president, Frank Notestein, on trips to Asia to review projects.

But a 1973 letter to the Population Council from May’s office revealed her increasingly tough stance on population control. Contraceptives had made too little impact, the letter said.

“Although we are conscious of the highly sensitive nature of this subject,” it said, “we feel confident that the leadership position of the council in the population field can be used to greatly accelerate the availability of abortion services worldwide on an ‘abortion upon request’ basis.”

— Sealed Borders and Sterilization

In August 1973, May secretly remarried, this time to her childhood friend and longtime companion Robert W. Duggan, the district attorney in the county that includes Pittsburgh.

When the marriage was disclosed, it made front-page news in Pittsburgh, in part because her new husband was fighting to stay out of prison amid a federal corruption probe.

Six months later, Duggan was indicted for evading taxes on payoffs he received from an illegal gambling ring. The same day, he was found dead at his country house, apparently from a self-inflicted gunshot.

By the end of the year, after more than two decades working with Planned Parenthood, May had resigned from the group. Two years later, her top aide delivered a stern message to Zeidenstein, the new president of the Population Council: Family planning and famine relief were a waste of money. Instead, “the U.S. should seal its border” with Mexico. According to a memo by Zeidenstein, May’s views were becoming so radicalized that “one got the impression” she favored compulsory sterilization to limit birthrates in developing countries.

Rockefeller, taken aback by May’s shift, wrote to her that he “had not been aware that differences of this seeming magnitude existed between us.” She responded that she would have severed ties sooner if not for her regard for him, and sent him the mission statement for a new group she had bankrolled, the Environmental Fund.

Buried in the document was a telling reference. “Immigration,” the statement said, “should also be brought into balance with emigration immediately.”

— Courting Courting

The Environmental Fund pushed mainstream concerns about overpopulation to the fringe and stoked opposition to immigration. Virginia Abernethy, a self-described “ethnic separatist” who became involved in the group, now called Population-Environment Balance, said in an interview that May was “the first person who comes to mind” of those who pushed the population-control movement to oppose immigration.

Through her work with the fund, the heiress struck up a close friendship with Garrett Hardin, a microbiologist and ecologist who argued that the modern welfare state encouraged overpopulation and ecological depletion. When May sent him news clippings about riots in Los Angeles, Hardin responded that the media was finally seeing that “maybe the blacks are less than saintly” and lamented “the predominant Latinity of apprehended criminals” where he lived in California.

“The hope of the future,” he said, “lies in the intelligent practice of discrimination.”

She also met John Tanton, a charismatic eye doctor and environmentalist from Michigan, who would leverage May’s financial resources to propel the budding anti-immigration movement forward.

Tanton, who died last month at 85, worked with Planned Parenthood and the Sierra Club and was the national president of Zero Population Growth in the 1970s. As the Baby Boom ebbed, he turned his attention to curbing immigration.

In 1978, immigration surged: The Border Patrol apprehended 863,000 unauthorized immigrants, the most in over two decades. Another 601,000 legal immigrants also arrived.

That November, Tanton wrote a nine-page proposal for funding from May to start a group called the Federation for American Immigration Reform, or FAIR.

“We plan to make the restriction of immigration a legitimate position for thinking people,” he wrote. May provided $50,000 to get the group off the ground.

FAIR’s early policy goals, some reflected decades later in proposals pursued by the Trump administration, called for not only an end to illegal immigration, but also a sharp reduction in legal migration. The group advocated increased funding and staffing for Border Patrol to police the southern frontier, campaigned against Cuban refugees and pushed to restrict public benefits for undocumented immigrants.

— An Enduring Influence

In 1996, May, then 68, established a new foundation, Colcom, to pursue her most important goals even after her death.

According to tax documents, Colcom has funded not only FAIR and other large organizations May helped create, but also lesser-known ones like the American Immigration Control Foundation, which has likened immigration to a “military conquest” with the effect of “substantially replacing the native population”; the International Services Assistance Fund, whose focus is promoting chemical sterilization of women around the world; and VDare, a website that regularly publishes white nationalists and whose name is derived from Virginia Dare, the first child of English settlers born in the New World.

Though her money and activism seeded the political landscape for Trump’s nativist policies — he argues that “the country is full,” claims Mexicans are “dirty” and “dangerous” and immigrants are stealing jobs — the heiress would not see the Queens real estate heir ascend to the presidency. May, who had pancreatic cancer, died at her home in 2005, at age 76. Her death was ruled a suicide by asphyxiation.

Thanks to her vast inherited fortune, May’s ideas, and causes, survive her.

“The issues which I have supported during my lifetime have not been popular ones in many cases, nor do I anticipate that they will be so in the future,” May wrote to Colcom’s board members in the group’s mission statement, calling on them “to exercise the courage of their convictions” after her death.

This article originally appeared in The New York Times.