A federal judge's ruling that President Trump illegally revoked a ban on oil and gas drilling in the Arctic Ocean could embolden future Democratic presidents to impose more significant limits on offshore drilling.

“We are seeing a successful legal assault on fossil fuel extraction,” said Michael Gerrard, an environmental law professor at Columbia University, noting other recent court setbacks to the Trump administration’s energy agenda. “It’s certainly helpful to the 'keep it in the ground' movement.”

U.S. District Judge Sharon Gleason of Alaska on Friday blocked Trump’s executive order that had reversed President Barack Obama’s ban on oil and gas drilling in most of the Arctic Ocean and a small portion of the Atlantic Coast.

Gleason, an Obama appointee, ruled that the Outer Continental Shelf Lands Act, which governs the offshore oil and gas leasing process for federal waters, allows presidents to unilaterally withdraw areas from offshore drilling, but does not permit a subsequent president to undo a predecessor’s protections.

She said only Congress could revoke Obama’s moves in 2015 and 2016 to shield 125 million acres of the Arctic Ocean, 98% of it, and about 3.8 million acres in the Atlantic from oil and gas drilling. The Trump administration is expected to appeal the decision in the 9th Circuit Court of Appeals.

“The ruling says the offshore drilling statute creates a one-way ratchet for presidential withdrawal of lands for energy development,” Gerrard said. “That would mean an administration that wants to prevent offshore drilling in certain waters can lock that decision in without fear the next president can reverse it.”

Citing risk to ecosystems and the ocean economy, presidents of both parties before Obama have blocked offshore drilling leasing in certain areas dating back to President Dwight D. Eisenhower, who permanently protected 75 square miles of coral reefs along the Florida Keys in 1960.

President George H.W. Bush used the offshore drilling law to ban leases off the coasts of Florida, California, Washington, Oregon, and Massachusetts, but the withdrawal only lasted 10 years. Congress, meanwhile, has a current moratorium on offshore drilling in the eastern Gulf of Mexico that expires in June 2022.

But the Obama ban in the Arctic and Atlantic oceans was the largest permanent use of the executive authority. And until Trump’s reversal of the action drew a court challenge by environmental groups, the concept of undoing a predecessor's withdrawal of offshore drilling areas had never been tested in court. The Outer Continental Shelf Lands Act does not include specific language allowing or stopping future presidents from reversing withdrawals.

Industry groups that support expanding offshore drilling contend Friday’s court ruling is significant and could encourage opponents to eye other more lucrative areas for permanent bans, such as the eastern Gulf of Mexico.

“The case clearly can be used in an adverse way to hinder our nation's energy and national security if this precedent is upheld and used again by future administrations,” said Erik Milito, vice president of upstream and industry operations for the American Petroleum Institute.

"It would not be unreasonable to assume Democrats running for president would make huge withdrawals under the Outer Continental Shelf Lands Act if this precedent is held up,” said an oil and gas industry official, who insisted on anonymity to speak candidly.

The Trump administration, before Friday’s court ruling, had prepared to dramatically expand offshore oil and gas drilling, releasing a five-year plan in January 2018 to open nearly all federal waters on every coast.

Interior is expected to release a revised plan in the coming weeks or months, after coastal governors and lawmakers from both parties have pressured Trump to scale back the plan.

The Arctic has been viewed as one of the sure bets for leasing, with local and federal politicians in Alaska supportive of drilling for its economic benefits to Alaskans.

The Friday court decision upholding a ban on leasing in the Arctic is a setback for the oil and gas industries, but their main interest is in opening parts of the eastern Gulf of Mexico.

Oil and gas production in the western and central Gulf of Mexico accounts for almost all current U.S. offshore production, and extending drilling further east just west of Florida could connect to existing infrastructure.

“The court taking the [Arctic Ocean] off the table is impactful, but in the grand scheme of U.S. energy policy, it's not as impactful as if there were an inability to include parts of the Eastern Gulf,” the industry official said.

Liz Klein, a former attorney at the Interior Department during the Clinton and Obama administrations, downplayed the possibility of future administrations aggressively banning drilling offshore if Friday’s court ruling stands.

She noted Obama undertook a lengthy consultation process before issuing his withdrawal and had originally considered opening portions of the Arctic and Atlantic oceans to oil and gas drilling before local pushback convinced him otherwise.

“There hasn’t been a seat-of-the pants energy policy to keep it all in the ground,” said Klein, who is deputy director of the State Energy and Environmental Impact Center at New York University. “It's hard for me to imagine there would be a change of administration in 2020 that all of a sudden pushed to withdraw all of the offshore areas.”