Republicans passed a bill Thursday to allow mining on hundreds of thousands of acres of previously protected wilderness in Minnesota, in a move that could forever alter congressional oversight over government rulemaking and public lands.

The Senate voted 50-49 to send the measure, recently approved by the House, to the president’s desk. It reverses a 20-year mining moratorium enacted by the Biden administration in 2023, covering over roughly 350 square miles near the Boundary Waters Canoe Area Wilderness. Only two Republicans voted against the bill, despite bipartisan concerns about the precedent it set for a future Democratic administration to block mining and fossil fuel exploration across the country.

“An activist, liberal administration could ride roughshod through a lot of our states, particularly more rural states that have large parcels of land and land agreements in place,” Sen. Thom Tillis, one of those Republicans, told NOTUS.

The vote marked a major expansion of the Congressional Review Act, a process Congress has used since the 1990s to overturn certain rules promulgated by government agencies by passing a joint resolution of disapproval. Previously, mineral withdrawals like the one in Minnesota were not considered “rules” subject to review by Congress. But now, fossil fuel leases, permits, land orders and mineral rights could all be fair game, giving Congress, rather than the executive branch of the federal government, more power to micromanage states’ land use.

“It’s an unprecedented procedural move that’s going to come back to haunt the Republicans,” Democratic Sen. Tina Smith warned in an interview Thursday. “It’s a huge mistake on their part. I had lots of Republicans tell me that they knew it was a mistake, but they voted this way anyway.”

Smith, a main player opposing the effort to open the wilderness areas in her home state to mining, held the Senate floor on Wednesday night in protest of the bill’s passage, which postponed the vote. The senator had been working for months to sway enough Republican colleagues to help defeat the bill, counting Republican Sens. Dave McCormick, Todd Young and Lisa Murkowski as swing votes. In the end, all three voted in support of the resolution after the White House weighed in on its behalf Wednesday, according to Smith’s office.

“It was sort of like the Eye of Sauron spotting the hobbits as they were kind of approaching Mount Doom,” Smith said about those Republicans, referring to the main antagonist in J.R.R. Tolkien’s “The Lord of the Rings.”

Democratic Sen. Martin Heinrich of New Mexico called the bill “a stain on what the Senate used to be” and declared “this is a dark day for this body” on the floor before the vote.

“Public lands are the one thing when I go home that unites my constituents from left to right, whether you’re a bow hunter or a bunny hugger — it doesn’t matter. They love our public lands. They care about our public lands. There are many places that we can mine and do it right,” Heinrich continued.

Murkowski, a moderate Republican from Alaska, where mining is a major industry, voted for the bill but conceded the precedent it sets is problematic.

“I agree with this policy, the policy that we’re talking about here,” Murkowski told NOTUS. “But I think that we may have set a precedent here on process that’s not going to be helpful.”

The Boundary Waters Canoe Area Wilderness near the U.S.-Canada border contains a vast, interconnected network of freshwater lakes, rivers and streams, and it’s home to threatened species like the Canadian lynx. Wild rice that grows in the area is sacred to many Native American tribes that reside there. There is not a mining project planned within the Boundary Waters themselves, but advocates have been concerned about toxic pollution flowing into that area.

At least seven Native American tribes — from Minnesota, Kansas, Wisconsin, South Dakota and Wyoming — wrote letters to senators and urged them to vote against the bill, citing concerns it would violate trust and treaty obligations the federal government has to the tribes and would be detrimental to the ecosystem. The National Congress of American Indians requested a hearing with the Senate Indian Affairs Committee on the issue.

Michael Fairbanks, chairman of the White Earth Nation in Minnesota, said in a news conference Thursday after the bill passed that this is an example of why holding Congress accountable and “up to date on treaty rights” is important.

“I’m going to pray again, you know, not to be so mad and try to figure out how we’re going to combat this and in a good way,” he continued. Fairbanks said he’s speaking with other tribal leaders across the country, as well as legal teams.

Twin Metals, a subsidiary of a large mining company based in Chile, wants to acquire leases to mine metal sulfides in the area.

“Any proposed project in this region, including Twin Metals, must undergo a yearslong, multi-agency regulatory review before earning permits to begin construction of a mine. The CRA restores this process, and projects must prove they can meet the stringent environmental standards that have long been in place in Minnesota before moving forward,” Kathy Graul, communications director for Twin Metals, said in a statement to NOTUS.