The Department of the Interior will announce recommendations to President Donald Trump Thursday on whether to rollback or remove national monument status from 21 designations.

DOI Secretary Ryan Zinke will advise reducing one monument, Bears Ears in Utah, and leaving six others alone. Zinke has not taken a public stance on the remaining 14.

Ultimately, the decision to reduce or remove a national monument’s designation lies with Trump — if he can make his case in court. Former Presidents Woodrow Wilson and Harry Truman both reduced national monument designations, but neither was challenged in court.

The Center for Biological Diversity (CBD) and other environmental groups will challenge Trump, CBD public lands program director Randi Spivak told The Daily Caller News Foundation.

“We are going to fight Trump’s scheme to rob Americans of their public lands and hand them over to greedy corporations,” Spivak said. “If Trump does what we think he is going to do, it will be a devastating loss for our country for generations … and we’ll see him in court.”

Organizations such as the Property and Environment Research Center (PERC) are prepared to defend the precedent set by Wilson and Truman.

“Often times when a national monument is declared, it restricts a multitude of different types of uses,” PERC research fellow Holly Fretwell told TheDCNF. “One size doesn’t fit all when the president takes a pen and says, ‘Okay we are going to restrict this area, you can’t use it for mining and grazing and timber harvest or whatever it might be’ … That doesn’t realize the different values on the landscape.”

The focus of the debate between these two camps is where the authority to reduce or remove national monuments lies: Congress or the president, according to High Country News.

PERC’s argument rests on the case made by Pacific Legal Foundation executive director Todd Gaziano and Berkeley law professor John Yoo.

Though the Antiquities Act does not explicitly give the president the power to restrict national monuments, Gaziano and Yoo argue the power is implicitly given.

“Not every grant of a power to create something must include the power to abolish it, but many do,” Gaziano and Yoo wrote in an American Enterprise Institute report. “Special circumstances might make revoking certain acts impossible, or that power might be withheld, but a presumption of revocability is often implied if the grant is silent.”

Some of the designations made by past presidents are illegal and not covered under the Antiquities Act. Designations under the act are supposed to be “confined to the smallest area compatible” necessary to protect the land, not giant swaths such as the nearly 1.5 million acre Bears Ears National Monument.

Current presidents are not obligated to honor the illegal actions of previous presidents, the Gaziano and Yoo argue.

Congress is given explicit control of public lands under the Constitution. The power still lies with Congress, because Trump doesn’t have explicit authority under the Antiquities Act to reduce the size of national monuments a group of professors argue in a co-authored paper, “Presidents Lack The Authority To Abolish Or Diminish National Monuments.”

They pointed to the 1976 Federal Land Policy and Management Act, which forbids the secretary of the Interior from modifying national monuments. With congressional records as evidence, they interpret the law and prohibition to extend to the president as well, though he is not expressly named in the law.

“The President lacks the legal authority to abolish or diminish national monuments,” the professors wrote. “Instead, these powers are reserved to Congress.”

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This article originally appeared in The Daily Caller