This post has been updated.

Interior Secretary Ryan Zinke signed a land-swap agreement Monday to allow a small, remote Alaska town to construct a road through the Izembek National Wildlife Refuge, a vast wilderness area that has been protected for decades.

The signing ceremony at Interior headquarters, which proceeded despite the government shutdown, marks a pivotal development in a political fight that has raged for more than 30 years. Alaskan politicians have argued the road would provide a route in poor weather for medical evacuations from King Cove to the closest regional airport, while environmentalists counter that it would fragment a pristine stretch of tundra and lagoons otherwise off-limits to motorized traffic.

Sen. Lisa Murkowski (R-Alaska) held a news conference after the event with not just Zinke and King Cove residents but the state’s governor, Bill Walker (I), Sen Dan Sullivan (R) and Rep. Don Young (R). She described the 925-person town as “a community in Southwest Alaska which, for over 30 years, has been trying to get a simple road, a simple road, to safety when it comes to air transport out of the areas.”

After Obama administration officials told her to “get over it,” Murkowski recalled, she kept the quote in a folder she carried with her constantly.

Several lawmakers credited President Trump for taking a personal interest in the issue. Walker noted that when he got a two-minute audience with Trump about energy issues, “the first thing he said was, ‘Let’s talk about that road.’”

Both supporters and critics of the agreement see it as an important precedent. The refuge, which provides a critical feeding ground for migrating birds as well as habitat for bears, caribou and other species, was established by President Dwight Eisenhower. All but 15,000 of its 315,000 acres have been designated as wilderness since 1980, and roads are traditionally banned in such areas.

The Washington Post first reported in October that Zinke was exploring the land exchange and confirmed this month that the agreement had been finalized.

The deal will transfer up to 500 acres of federal land to the King Cove Native Corporation in exchange for tribal land of equal value. Speaking to reporters on Monday, spokeswoman Della Trumble said residents were “very thankful” for the deal, which will allow them to construct an 11-mile road. “It seems almost unreal,” she said.

Environmentalists said the decision will place the birds that migrate along the Pacific Flyway in peril. In spring and fall, nearly the entire global population of emperor and Pacific black brant geese stop in Izembek to eat. In winter, tens of thousands of the threatened Steller’s eider sea ducks stay there and molt.

“We have a globally recognized wetland, an absolutely unparalleled habitat for so many iconic species, designated wilderness, and this administration just ran right through it all,” said Defenders of Wildlife President Jamie Rappaport Clark, who served as U.S. Fish and Wildlife Service director under President Bill Clinton. “What a sellout. If they can do this in as biologically valuable and internationally recognized [a] place as Izembek, there is not one public land base that is off limits to this administration.”

The question of how to treat King Cove, located on the southern tip of the Alaska Peninsula, has bedeviled federal officials. As part of an agreement brokered during the Clinton administration, taxpayers spent more than $50 million to fund a modern telemedicine clinic and a hovercraft that covered the distance between the village and Cold Bay in 20 minutes. Multiple federal analyses endorsed alternative solutions to the road project — such as a marine ferry to replace the hovercraft residents sold off — and suggested bad weather could make the gravel road impassible at times.

Yet local and state officials said they can manage driving though such conditions better than traveling by air and boat. Between 1980 and 1994, 12 people died during aerial medical evacuations en route to the hub airport, though no residents have died during such evacuations since then.

King Cove officials said that while details of the exact land exchange will have to be negotiated over the next several months, it will likely traverse the southern part of the refuge.

The 1964 Wilderness Act bars new roads and the use of motorized vehicles in areas designated under the law except in rare instances — such as to provide access for the development of existing mining claims — and there appears to be no precedent for the executive branch permitting those activities for other reasons. The Wilderness Society and other groups successfully blocked the Forest Service last year from authorizing four miles of road construction in Idaho’s Frank Church-River of No Return Wilderness to access a long-dormant gold mine.

Asked Monday if Interior had done a new environmental analysis before approving the land swap, Zinke said a more detailed analysis would come once a proposal for constructing the road is finalized. According to King Cove City Manager Gary Hennigh, no new environmental review was conducted since Trump took office.

Zinke said he will not voluntarily release any documentation on this front, telling reporters they had the right to submit requests under the Freedom of Information Act. But he said the department had found “no significant issue” environmentally. “Just the opposite.”

Nicole Whittington-Evans, Alaska regional director for the Wilderness Society, an advocacy group, said in an email that the agreement “is the result of backroom negotiations that kept the public completely in the dark and ignored the Interior Department’s science-based conclusions against the road.”

“Sadly, the Trump administration is charging ahead with the effort to build an unnecessary road through this extraordinary wilderness area — regardless of the damage it would cause to Izembek’s globally significant wildlife habitat — because it fits their agenda of selling off or trading America’s public lands for development,” she said. “We are committed to protecting Izembek, and plan to challenge the land exchange in court to ensure this irreplaceable wilderness area remains intact.”

Sullivan called support for the road’s construction “an issue that unites Alaskans” regardless of party affiliation, with state and local officials prepared to join with federal officials in fending off any legal challenges to the exchange.

“They’re going to fight like crazy against that, because we know this decision is the right decision, for Alaska, for the community and for the country,” he said.

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