One of America’s bedrock conservation and preservation laws, the Antiquities Act was originally conceived as a response to an epidemic of looting. For decades, relic hunters and curio seekers systematically stripped artifacts from historic Native American sites across the Southwest. There were no laws to stop the likes of amateur archaeologist Gustaf Nordenskiöld, who brought hundreds of artifacts from Mesa Verde, Colorado, back to his home in Sweden in the 1890s. Most of his finds are now at the National Museum of Finland in Helsinki.

“No European country would be so heedless of her archaeological treasures,” exclaimed one turn-of-the-century editorial. “Unless some check is made upon the vandalism of our prehistoric remains in the Southwest there will eventually be none worth protecting.”

One of the many Americans outraged by this widespread plunder of our history was President Theodore Roosevelt. “We have fallen heirs to the most glorious heritage a people ever received,” he once declared, “and each one must do his part if we wish to show that the nation is worthy of its good fortune.” In June of 1906, after both the House and Senate voted in approval, Roosevelt signed legislation creating Mesa Verde National Park—the first national park intended to “preserve the works of man.” Just a few weeks prior, he had signed the Antiquities Act into law, and soon used it to save quintessentially American places such as the Grand Canyon, the Petrified Forest, and Chaco Canyon.

Ever since, presidents of both parties have used the Antiquities Act more than 150 times to designate iconic places that tell our story, from parts of Sequoia National Forest to the Marianas Trench to President Lincoln’s Cottage and the Statue of Liberty. But now this critical federal preservation tool has come under direct and unprecedented assault.

Last year, the Trump administration reduced the size of both the Bears Ears and Grand Staircase-Escalante National Monuments in Utah. This action erases protections for more than 2 million acres of historic land owned by the American public and replete with archaeological treasures that rival those of Mesa Verde. It exposes these thousands of extraordinary and irreplaceable archaeological sites in Utah to harmful oil and gas drilling, mining, and even looting and vandalism—the exact threats to our heritage that the Antiquities Act was created to prevent in the first place.

The National Trust is now working with a broad coalition of Native American, conservation, outdoor industry, and science organizations to challenge this reversal. For more than a century, the Antiquities Act has helped to forge a national system of public lands that is the envy of the world. As heirs to Theodore Roosevelt’s proud legacy of preservation, we will do our part to protect those historic lands for future generations, as well as the act that secured them.