The "House on Fire" ruins in Mule Canyon, near Blanding, Utah, are part of the Bears Ears National Monument. (Rick Bowmer/Associated Press)

Robert D. Rosenbaum is a retired partner of the law firm of Arnold & Porter Kaye Scholer LLP and is chairman of the Mid-Atlantic Regional Council of the National Parks Conservation Association.

Critics of national monuments created by President Obama — particularly the Bears Ears monument in Utah — have long argued that President Trump should revoke Obama’s orders establishing them. Meanwhile, the House Natural Resources Committee declared this month that it plans to work with the Trump administration to identify which declared monuments should be “rescinded or diminished in size.”

On March 8, Rep. Raúl M. Grijalva (Ariz.) — the ranking Democrat on the committee — wrote a letter to Interior Secretary Ryan Zinke asking for his opinion on the president’s power to take such actions. But regardless of what opponents of the monuments think about the matter, the president has no unilateral power to revoke a national monument.

The Antiquities Act of 1906 empowers the president to establish national monuments to protect federal land containing “historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest.”

Many U.S. national parks began as national monuments established under the act, including the Grand Canyon, Acadia, Zion and Olympic. Thanks to the important additions to our national park system over the past eight years under the Antiquities Act, visitors can now explore pivotal moments in the fight for racial equality at Birmingham Civil Rights National Monument; experience the vast Joshua tree forests and rich cultural history of the West at Castle Mountains National Monument; and reflect on the long struggle for civil rights at Stonewall National Monument in New York.

The Antiquities Act does not say the president may rescind such designations, but proponents of revocation argue that the president has the implied power to do so. They argue that the Constitution’s grant of executive authority to the president is broad and that this is merely one of the unstated powers encompassed within that broad grant.

The problem with that argument is that we are not here dealing with any power granted the president under the Constitution, but instead with the management of federal lands. The Constitution’s property clause grants that power not to the president, but exclusively to Congress.

In the Antiquities Act, Congress chose to delegate a portion of this power to the president to designate national monuments. Therefore, the issue is not whether the Constitution’s grant of executive power conveys the power to revoke national monuments, but whether Congress has given that power to the president.

In 1938, when asked by President Franklin D. Roosevelt whether he could abolish a national monument, Attorney General Homer Cummings opined that the president had no such power. That conclusion was the basis on which Congress reorganized the relevant parts of the laws relating to federal land management in the Federal Land Policy and Management Act of 1976.

Here is what the 1976 House of Representatives’ committee report said: The act “would also specifically reserve to the Congress the authority to modify and revoke withdrawals for national monuments created under the Antiquities Act.” In effect, under principles long established by the Supreme Court, Congress adopted the 1938 opinion of the attorney general in 1976. And since 1938, no president has attempted to revoke a national monument unilaterally.

Members on the Natural Resources Committee say that a president may nevertheless “diminish” the size of a national monument. Any attempts by the president to remove land or features that would undermine the purposes and values for which the monument was originally created, however, would be a partial revocation of the monument. The president does not have the power to do in part what he cannot do in full.

President Barack Obama used his authority under the 1906 Antiquities Act to create national monuments 34 times, more than any other president. Now Trump's order to review National Monument designations has been completed. Will those monuments continue to stand? The Post's Juliet Eilperin explains. (Daron Taylor/The Washington Post)

For more than 100 years, presidents of both parties have used their executive power to establish national monuments to preserve places of national historic significance and natural beauty for the enjoyment of all Americans and future generations. No president acting alone has the power to undo those protections.