The minute President Trump entered the Oval Office, President Barack Obama’s environmental legacy was in danger. The clean air and water regulations and the land protections he established, all without Congress’s assent, were as fragile as some of the precious habitat they were meant to protect.

Yet Thursday brought indication that Mr. Trump may unravel the environmental achievements of more than one president. The Post reported that Interior Secretary Ryan Zinke sent recommendations to the White House that include scaling back some of the most prominent national monuments created in the past three decades. Unsurprisingly, Bears Ears National Monument, which Mr. Obama created at the end of his presidency, is top on the list for downsizing. But also on the chopping block is the nearby — and utterly spectacular — Grand Staircase-Escalante National Monument, which President Bill Clinton established in 1996. Some monuments that are not set to shrink could nevertheless lose some protection. More fishing could be permitted in sensitive marine monuments, for example.

The details are secret, which is a problem in itself. What is clear enough is that an extensive tour of southern Utah and consultation with local tribes, who pushed for preservation, did not impart on Mr.?Zinke the proper awe for the natural wonders he is now endangering. In June the secretary issued an initial report on Bears Ears that did not suggest restraint in rolling back the national monument.

Narrowly interpreting the law under which national monuments have been established, Mr. Zinke indicated that only isolated “rock art, dwellings, ceremonial sites, granaries” in Bears Ears deserve national monument protection, arguing that it was appropriate only to “identify and separate the areas that have significant objects.” This is not how presidents have used the law since the days of Teddy Roosevelt, who set aside more than 800,000 acres of the Grand Canyon. Presidents for decades have preserved spectacular, irreplaceable and integrated natural landscapes, not just one butte or cliff dwelling at a time.

When we asked the Interior Department for more information, a spokeswoman pointed to sections of Mr. Zinke’s report that called for Congress to establish other sorts of protections for the land he would withdraw from Bears Ears, perhaps declaring some of it a national recreation area. If Congress wants to move Bears Ears’ boundaries or establish different levels of protection on the land, it can do so. The president should not withdraw protections before that happens. The same goes for Grand Staircase, a breathtaking area of the country that was saved the indignity of having a coal mine drilled into it only because of Mr. Clinton’s actions 20 years ago.

Some of those pushing to reopen these lands see them as just another place to graze or mine. They are wrong. These places are unique. Grand Staircase’s jutting rock formations tell a geologic story over hundreds of miles. Bears Ears’ rust-red landscape is replete with streams, buttes, natural arches and Native American artifacts. Landscapes of this scale and spectacle are unique and irreplaceable. The nation owes it to future generations to preserve them.

—The Washington Post, Aug. 27, 2017