President Donald Trump's repeal of a U.S. Fish and Wildlife rule banning most predator control on Alaska refuges revives a long-standing battle between the state and federal government.

The repeal generated advance warning from wildlife groups that Alaska was about to start gassing wolf pups in dens — and celebration from Gov. Bill Walker's office and Alaska's congressional delegation as a win for state sovereignty.

But a former USFWS regional director says the repeal simply restores the long-standing impasse between the state and the feds when it comes to predator control on federal lands.

Before the so-called Alaska rule went into effect in September, the Alaska Board of Game regularly called for predator control in areas that included federal wildlife refuges.

The U.S. Fish and Wildlife Service regularly said no, said Geoff Haskett, former Alaska regional director of the agency who now serves as acting president of the nonprofit National Wildlife Refuge Association.

"With the regulation revoked, the Fish and Wildlife Service will go back to where they were before they got the regulation done," Haskett said. "If the state says, 'We want to do predator control' in an area where it's not allowed by federal managers, the answer's still going to be 'No' from the Fish and Wildlife Service."

The service manages 16 refuges totaling nearly 77 million acres, an area only slightly smaller than New Mexico.

The Fish and Wildlife Service rule banned predator control on refuges in Alaska unless it was "necessary to meet refuge purposes, federal laws or Service policy" and was based on "sound science and in response to a conservation concern."

That ruled out actions to help subsistence or other hunters on Alaska's federal refuges, state officials said.

Bruce Dale, the director of the Alaska Department of Fish and Game, said this week that the Alaska rule would have "closed the door" to the state proposing predator control on refuges to increase moose or caribou for hunters.

Before the repeal, the Fish and Wildlife Service could have categorically denied, say, a state request for wolf control on federal Yukon Delta refuge lands along the Lower Kuskokwim River.

"Now they have to look at their refuge purposes honestly and determine whether it's the best thing to do," Dale said. "It makes them do their job."

A spokesperson for the U.S. Fish and Wildlife Service said officials were told not to comment on legislation and emailed a statement: "Hunting is deeply rooted in American tradition and is a way of life for many Alaskans who often depend on the land and resources. We all share the same goal of conservation of wildlife and habitat for future generations and we look forward to working closely with the State of Alaska to ensure that mission is met."

Monday's repeal came after months of criticism about the rule from the governor's office and Alaska's congressional delegation.

The state filed suit in January. U.S. Rep. Don Young in February introduced a resolution of disapproval under the Congressional Review Act to overturn the Alaska rule, calling it "entirely inappropriate" and a violation of federal law that usurped the state's authority to manage fish and game in Alaska.

State and federal agencies fall under dueling mandates when it comes to predator control.

The Fish and Wildlife Service is required to manage refuges "to ensure that … biological integrity, biological diversity, and environmental health are maintained."

Under a 1994 Alaska state law prioritizing high levels of moose, caribou and sheep for hunters, the state's "intensive management" predator-control policy kicks in when prey numbers drop low enough.

The Alaska rule sprang from concerns about increasingly aggressive state predator control policies as well as liberalized hunts near refuge lands, officials say.

The state has rarely succeeded in getting predator control on federal refuges approved, including a bid to kill wolves from helicopters on Unimak Island within the Alaska Maritime National Wildlife Refuge.

State predator control doesn't need to be on refuge lands, however, to cut into predator populations on refuges.

Roughly 1,100 wolves were killed in Alaska every year on average between 2003 and 2014, according to Alaska Department of Fish and Game statistics. Predator control — again, on average — killed 12 percent of them.

State-approved wolf harvest including hunting and trapping outside Denali National Park led to the potential demise of a long-studied wolf pack often glimpsed by park visitors.

A Fish and Game wolf control project outside Yukon-Charley Rivers National Preserve sharply reduced radio-collared packs being tracked by Park Service biologists in 2013.

Several years ago, during Haskett's tenure as director, the Fish and Wildlife Service for two years in a row closed all hunting on the Kenai National Wildlife Refuge because the Board of Game authorized expanded bear hunts that could include females.

"We had to close down the refuge because there were just too many brown bears being harvested," he said.

The state relies on various methods to enact predator control. For wolves, those methods can include private pilots shooting them from planes and Fish and Game staff shooting them from helicopters.

The Department of Fish and Game did gas wolf pups in dens but only in one program in 2008 and 2009, officials say. That was on the southern Alaska Peninsula when pups in two dens were killed with carbon monoxide after biologists killed their mothers as part of an experiment to boost caribou calf survival.

That was the only time pups were removed from dens, Fish and Game spokesman Ken Marsh said.

More broadly, the state isn't currently conducting any predator control on federal refuge lands, Marsh said, "and I'm unaware of any plans to do so."

Any future Board of Game proposals for predator control on refuges would fall under federal environmental laws prior to approval, Dale said.