The Endangered Species Act was created by a somewhat unlikely hero: President Richard M. Nixon. Although Nixon expressed personal disgust with environmentalists in private, he also recognized that Americans’ interest in the environment was not a passing fad.

Nixon used his presidency to champion sweeping legislation to protect America’s air, water and animals. These accomplishments are often forgotten, overshadowed by the political disgrace that caused him to resign the presidency less than a year after he signed the law.

Despite the political conservatism that fueled Richard Nixon’s election, the United States became increasingly aware of environmental issues during the 1960s and early 1970s. In 1962, Rachel Carson’s Silent Spring exposed the environmental effects of widely used pesticides like DDT, and in 1969 the United States experienced what was then its largest-ever oil spill in Santa Barbara due to a leak at an offshore oil rig. Images of pristine beaches turned into oil slicks and reports of thousands of dead animals further galvanized the nascent environmental movement.

Suddenly, the public wanted answers about the environment, and the new president obliged. In 1969, he created the Council on Environmental Quality, an executive office that coordinates environmental efforts. He took things even further during his first State of the Union Address in 1970, proposing a sweeping clean air and water initiative and putting environmentalism front and center.

“The great question of the seventies is, shall we surrender to our surroundings, or shall we make our peace with nature and begin to make reparations for the damage we have done to our air, to our land, and to our water?” he said.

Though Nixon didn’t mention animals in the address, it was clear that he considered them a vital part of the environment. The nation had already identified an initial list of endangered species through the Endangered Species Preservation Act of 1966 and widening its scope, including establishing fines for poaching endangered species, with the Endangered Species Preservation Act of 1969.

Nixon kept pushing, and in 1970 he created the Environmental Protection Agency. Then, in 1972, he addressed Congress about his expanding environmental agenda. “My new proposal would make the taking of endangered species a Federal offense for the first time,” he told Congress, “and would permit protective measures to be undertaken before a species is so depleted that regeneration is difficult or impossible.” Nixon had just requested the most sweeping animal protection legislation of its day—the Endangered Species Act of 1973. Congress complied and he signed it into law on December 28, 1973.

The new law didn’t just protect individual species; rather, it focused on their habitats, too. “Nothing is more priceless and more worthy of preservation than the rich array of animal life with which our country has been blessed,” Nixon told the nation during an address announcing that he’d signed the legislation.

Over the years, the Endangered Species Act dramatically increased the number of endangered and threatened animals. Before the law, only 417 breeding pairs of bald eagles were known to live in the lower 48 states. By 2006, there were more than 9,700 pairs. The wolf population grew from just a few hundred before the ESA to more than 5,000 today.

So should Nixon be remembered as a green champion? The president actually derided environmentalists in the privacy of the Oval Office. Environmentalists wanted to “go back and live like a bunch of damned animals,” he told Ford Motor Company chairman Henry Ford during a 1971 meeting. “They’re a group of people that aren’t really one damn bit interested in safety or clean air. What they’re interested in is destroying the system.”

But Nixon knew a social movement when he saw one. And, as Meir Rinde notes for the Science History Institute, Nixon was personally fond of national parks and the outdoors. More than anything, Nixon was a pragmatist. He may not have personally resonated with environmentalism, but he recognized people’s sense of urgency behind the movement and responded.