It was in this arena that John Muir, a conservationist who would help to fundamentally shift the the way the country thought about its land, wrote these words in The Atlantic’s 1897 August issue: “Notwithstanding all the waste and use which have been going on unchecked like a storm for more than two centuries, it is not yet too late, though it is high time, for the government to begin a rational administration of its forests.”

It was this vision—expanded to include not only America’s forests, but also her mountains and canyons, plains and oceans—that would come to be recognized as the country’s “best idea.” In Presidents and the American Environment, historian Otis Graham writes that by the late 1800s, widely-circulated articles like Muir’s had brought the issue into public consciousness. Sportsmen, too, were alarmed by the marked decline in certain species due to over-hunting and deforestation, and pushed for natural-resource regulation. Congress, “intermittently unhappy with the situation on the public lands,” began taking into account complaints from these small, elite groups—conservationists, hunters, and scientifically-minded bureaucrats alike.

When Theodore Roosevelt, a naturalist and hunter who was also friends with Muir, assumed the presidency in 1901, he made land protection a priority. The convergence of increasing public awareness and governmental concern spurred a “social and political mobilization,” according to Graham.

The Antiquities Act, signed by Roosevelt in 1906, was the clearest example of this shift: It gave presidents the power to protect land by declaring national monuments. The act was brief, specifying that the sites need only be “objects of historic and scientific interest” to warrant protection. Over time, government-owned land became an intrinsic part of American life—a reflection of the country’s principles. “The parks do not belong to one state or to one section,” said Stephen Tyng Mather, who served as the first director of the National Park Service from 1917 to 1929. “They have been democratized.”

Today, over 630 million acres of U.S. land are protected through various designations. Last year, nearly 331 million people—more than the country’s entire population—visited national parks.

Still, land preservation has been a point of contention between Republicans and Democrats for years, from William Howard Taft’s quiet revision of some of Roosevelt’s monuments to a drawn-out battle surrounding Grand Teton National Park. Michael Kraft, co-author of Environmental Policy: New Directions for the Twenty-First Century, said that Republicans are generally less supportive of “protecting large swaths of land” because of economic interests and what they see as an “abuse of power” by some presidents. “But the prevailing pattern is that presidents of both parties have [made designations],” he said.