The Trump administration’s best hope to overturn a March 29 lower court decision shutting down oil and gas drilling off the Alaskan coast may lie across the country at the U.S. Supreme Court, environmental lawyers said.

All five conservative justices on the high court have shown skepticism about agency claims of authority where Congress hasn’t clearly delegated it—the core issue in the Alaska case. A federal district judge struck down an executive order from President Donald Trump that opened Arctic waters to oil and gas drilling.

The Outer Continental Shelf Lands Act can be seen as a “one-way ratchet” that grants the president the right to withdraw certain areas for drilling, but not for revoking prior withdrawals, said Patrick Parenteau, an environmental law professor at Vermont Law School in Royalton, Vt., and currently a visiting professor at the University of New Mexico law school in Albuquerque.

“That would leave it to Congress to decide whether to either amend the OCSLA or revoke or modify any prior withdrawal,” Parenteau said. “That might appeal to the conservative view of the separation of powers doctrine.”

Conservatives have recently been ramping up their attacks on long-standing agency deference doctrines as part of a broader plan to give the power to interpret laws to Congress and the courts.

The March 29 decision by U.S. District Judge Sharon L. Gleason of the U.S. District Court for the District of Alaska restores Obama-era protections for the Chukchi and Beaufort seas in the Arctic Ocean, as well as waters in the North Atlantic coast.

Randall Luthi, president of the National Ocean Industries Association, said he thinks an appeals court will have good reason to review the Alaska decision because the federal leasing process is revisited every five years.

That gives the administration a chance to review new information about the need for oil and gas leasing and its environmental impacts, according to Luthi.

“Congress certainly didn’t intend these things to be set in stone forever,” he said.

A Close Call

But even at the Supreme Court, the decision would be a close call, because the justices would still have to grapple with the further question of whether Trump’s reversal was based on “neutral and objective factors,” according to Parenteau.

The late Justice Antonin Scalia ruled in a leading administrative law case from 2009 that a federal agency needs a more detailed justification for reversing course if it wants to disregard “facts and circumstances that underlay or were engendered by the prior policy.”

Further, “arguing that Congress meant the opposite of what it said in a statute is always an uphill battle in court, and really would be in the current Supreme Court,” said Hillary Hoffman, a natural resources law professor at Vermont Law School.

A late March Supreme Court decision about an Alaska moose hunter who wanted the right to ride his hovercraft on a state river showed that the justices will take Congress at its word when interpreting statutory powers, according to Hoffman.

Case law has also firmly established that Congress, under the property clause of the Constitution, decides what authority to delegate to the Secretary of the Interior, and reserves to itself any powers not delegated, such as the power to remove conservation protections, according to Hilary Tompkins, an environmental lawyer at Hogan Lovells in Washington and a former solicitor for the Interior Department.

The property clause generally gives Congress the authority to regulate and dispose of territory or other federal government property.

Clock Is Ticking

The clock is also working against the Trump administration. An appeal of the Alaska decision would first go to the U.S. Court of Appeals for the Ninth Circuit, meaning a Supreme Court review almost certainly couldn’t happen until after the 2020 election—by which time a Democratic president who doesn’t want to open up offshore drilling could be in office.

Moreover, lower-court decisions often color the way appeals courts view the same set of facts, according to Sean Hecht, an environmental law professor at the University of California, Los Angeles.

“In theory, an appellate court should not be giving deference to a lower court’s determination of a purely legal issue,” Hecht said. “In real life, if a court writes a well-reasoned decision and it comes from a respected judge, that’s going to be something the court of appeals takes into account.”

DOJ ‘Won’t Let This Lie’

The Trump administration hasn’t signaled whether it will appeal the decision. But an appeal seems likely, because the administration and such allies as the state of Alaska and the American Petroleum Institute—both of which were intervenors in the litigation—are determined to expand drilling.

Further, the Justice Department “won’t let this ruling lie, as it jeopardizes their argument in other cases involving the Antiquities Act,” Hogan Lovells’ Tompkins said.

The Antiquities Act allows the president to protect buildings, sites, and “objects of historic or scientific interest by designating them as National Monuments,” according to information on the National Park Service website.

The Alaska ruling doesn’t establish legal precedent, but other courts “will refer to this as potentially persuasive,” Hecht said.

That means the decision could apply to the Trump administration’s plans to reduce national monuments onshore. The Antiquities Act, like OCSLA, doesn’t have language directly addressing whether a president has the authority to undo a previous president’s decision.

Natalie Barefoot, an environmental justice professor at the University of Miami, predicted that the administration on appeal will likely take up the same arguments it did in the lower court.

No Case Law

Others said the lack of precedent makes it difficult to predict which way an appeals court will rule.

“There’s really no case law on the issue, so it’s a matter of statutory interpretation,” said Alexandra Klass, an environmental law professor at the University of Minnesota Law School. “No president has tried to undo the work of his predecessor using these statutes in such a radical way.”

Law scholars broadly predicted the Ninth Circuit will uphold the Alaska district court ruling.

“I would assume the Ninth Circuit would affirm because this decision is firmly based in the Constitution and section 12(a) of the Outer Continental Shelf Lands Act, which is very clear about the president’s power to prevent offshore drilling and other forms of mineral development by withdrawal,” Hoffman said.

Appeal Nearly a Certainty

Virtually no observers thought the Trump administration will accept Judge Gleason’s ruling without a challenge.

Parties on the losing end of a district court decision do sometimes opt not to appeal, especially if they don’t want to risk another loss in the appeals courts, “which would carry more weight,” said Thomas Jackson, an environmental lawyer at Baker Botts LLP in Washington.

“But that seems unlikely here,” Jackson said.