ICYMI We have maps that show Trump's plans to rip apart Utah's Bears Ears and Grand Staircase-Escalante... and they aren't pretty.https://t.co/B80XWVGelg #StandBearsEars#SaveGrandStaircase pic.twitter.com/qCvwouNxng — Wilderness Society (@Wilderness) December 1, 2017

Maps of draft proposals that would drastically shrink the boundaries of two U.S. national monuments in southern Utah’s Red Rock country leaked Thursday to multiple organizations. They are visible in the tweet embedded above.

According to this draft proposal, Bears Ears National Monument would be reduced by 85 percent, from its current 1.35 million acres to 201,397 acres. Grand Staircase Escalante would be cut by half, from nearly 1.9 million acres to 997,490 acres. Grand Staircase would be split into three areas, each named as a separate monument. Bears Ears would be divided into two monuments. Last January, Utah’s congressional delegation asked Trump to abolish or drastically reduce both monuments.

The U.S. Interior Department declined to comment, but an administration official said the leaked versions do not necessarily represent the final boundaries that will be sought. President Trump is scheduled to announce his intended changes to both monuments at a rally in Salt Lake City on Monday. (Learn about world monuments in danger.)

Bears Ears: See America’s Sacred and Stunning New National Monument

The maps are likely to stoke opposition from environmentalists, conservationists, outdoor enthusiasts, and Utah residents. Five Native American tribes involved in creating Bears Ears and multiple conservation groups vowed last spring to sue the administration as soon as Trump acts to reduce the size of any monuments in the state. A protest rally in Salt Lake City is being organized by the Southern Utah Wilderness Alliance.

Trump had previously called for a review of more than two dozen national monuments that had been created over the past few decades, with the goal of addressing the complaints of some politicians and local people who had objected to their designations and in an attempt to spur more oil and gas drilling, mining, and other resource extraction activities. Trump has called the past creation of monuments by Barack Obama “an egregious abuse of power.” (Learn more about this monument rethink.)

That review has become a “fundamental fight about the value of our public lands and we are reopening a question that was settled a long time ago,” Sharon Buccino, director of land and wildlife programs at the Natural Resources Defense Council, previously told National Geographic. “It is part of our identity as Americans to protect some of our lands. That is what is at the root of this fight.” (See the monuments targeted for review in maps.)

Created in 2016 by President Obama and named for two buttes that jut above the ridgeline, Bears Ears protects cliff dwellings and one of the West’s largest collections of tribal artifacts. Created in 1996 by President Clinton, Grand Staircase Escalante is a series of cliffs and plateaus descending in multi-colored stair-steps from Bryce Canyon in southwest Utah to the Grand Canyon. The monument also protects paleontological and tribal archeological sites, as well as 300 animal species, including the endangered desert tortoise.

If the president decides to go ahead with the reductions to the monuments as drafted, they will be the first national monument reductions-in-size since the early 1960s, and will exceed by far previous monument boundary adjustments.

The brewing legal fight will likely reach the Supreme Court. The court will be asked to determine if the 1906 Antiquities Act, which grants the president power to create monuments, also grants presidential authority to abolish or reduce monuments. An opinion authored by President Franklin Roosevelt’s attorney general argued in 1938 that presidents have no such power to abolish monuments. That position has been accepted by all of Roosevelt’s successors until now.

Presidents have revised national monument boundaries, most notably President Woodrow Wilson’s halving of the Olympic National Monument in Washington state in 1915. None of those boundary adjustments have ever been challenged in court, leaving the question unsettled.

The proposed changes call for Grand Staircase Escalante to be remade into three separate monuments—Grand Staircase National Monument, Kaiparowits National Monument, and Escalante Canyons National Monument. Bears Ears would be split into two monuments—Indian Creek National Monument and the Shash Jaa National Monument. Trump’s opponents will likely try to argue in court that he abolished the two existing monuments and replaced them with five smaller monuments.

Trump’s decision also creates several other thorny legal and political issues regarding congressional powers and management of federal lands whose designation may change, says Robert Keiter, a University of Utah law professor and director of its Wallace Stegner Center of Land Resources and the Environment.

“When Congress adopted the Federal Land & Policy Management Act in 1976, it appeared to reserve to itself the power to modify or revoke national monument designations, which provides a powerful legal argument for monument supporters in any legal challenge to the president’s actions,” Keiter says.

In the case of Grand Staircase Escalante, Congress also has already adjusted its boundaries and written the changes into law.

“Because Congress approved a massive land exchange with the state of Utah following designation of the Grand Staircase Escalante National Monument, it has essentially ratified the boundaries of that monument, and the president does not have authority to override this congressional action, given that Article IV of the Constitution grants Congress—not the president—broad authority over the public lands.”

If Trump’s changes withstand a court challenge, then there’s the practical matter of managing federal land.

“The President’s monument reduction action invites future presidents to take similar actions to any monument they might dislike, and it invites other presidents to reverse these actions and reinstate the original boundaries, creating extraordinary uncertainty for public land managers and users,” Keiter says. “In short, this would amount to an intolerable situation for everyone.”