ERIC THAYER/Reuters Sen. Lisa Murkowski (R-Alaska), always keeps us guessing where she'll come down on major Senate votes.

WASHINGTON ― For all the speculation about Sen. Lisa Murkowski (R-Alaska) and whether she’ll vote for Supreme Court nominee Brett Kavanaugh, there is an issue beyond abortion rights perhaps weighing more heavily on her as she makes her decision: protections for Alaska Natives.

Advocates for Alaska Natives, who were crucial to Murkowski’s re-election in 2010, tell HuffPost they’ve been flooding her office all week and urging her to oppose Kavanaugh.

They’re raising concerns about his record on climate change, which is already causing real damage in Alaska. As a judge on the U.S. Court of Appeals for the D.C. Circuit, Kavanaugh in 2017 held that the Environmental Protection Agency lacks the authority to regulate hydrofluorocarbons, chemicals linked to global warming. They’re also unhappy with his record on voting rights. Kavanaugh voted in 2012 to uphold a South Carolina voter ID law that disenfranchised more than 80,000 minority registered voters.

The most pressing matter, however, is a case the Supreme Court is reviewing on Nov. 5 that could devastate Alaska Natives’ subsistence fishing rights. The case, Sturgeon v. Frost, raises questions about who has the authority to regulate water in national parks in the state ― the federal government or the state of Alaska. The case arose after Alaska resident John Sturgeon, who was on an annual moose-hunting trip, was riding a hovercraft on a river running through a national park when Park Service officials threatened to give him a citation. Sturgeon is arguing that his ability to use his hovercraft in this scenario is about states’ rights and that federal authority should be eliminated.

Kavanaugh has previously ruled to limit federal power in cases before him. If he gets confirmed and votes with the other four right-leaning justices in favor of Sturgeon’s argument, it will destroy the way of life for tribal communities who rely on subsistence fishing in protected federal waters, some Alaska Native rights groups say.

“This would be a death knell to us in Alaska, absolutely,” said Heather Kendall-Miller, an Alaska Native and an attorney with the Native American Rights Fund. “If this goes down, Alaska will be in a state of chaos when the fishing season begins. There will be lots of civil disobedience. It will be explosive.”

Kendall-Miller wrote an op-ed in the Anchorage Daily News this week laying out some of these concerns about Kavanaugh. She said her organization has been in talks with Murkowski’s staff and has been meeting with the senator’s office this week.

“We continue to cycle people through her office with these concerns,” she said.

Andy Cross via Getty Images Alaska Native Michael Dirks collects a silver salmon he caught while fishing in the Chukchi Sea in 2010. His Point Hope village has lived a mostly subsistence life of hunting and fishing for thousands of years.

Representatives from the National Congress of American Indians have also been meeting with Murkowski and raising concerns. NCAI President Jacqueline Pata has highlighted Kavanaugh’s record on climate change.

“Native foods and fisheries are declining, and tribal access to traditional foods and medicines is often limited by reservation boundaries,” Pata said in a statement.

A Murkowski spokeswoman did not respond to a request for comment on how much of a factor Alaska Natives’ concerns are in her decision on Kavanaugh.

But the Republican senator owes her 2010 re-election to tribal communities, so anything harmful to them is going to be a significant issue for her.

That year, Murkowski unexpectedly lost her primary to a tea party challenger. She responded by running as an independent, launching a write-in campaign and winning the race against all odds. Whose support didn’t she have? The Republican Party. Whose support did she have? Alaska Natives, who turned out for her and fueled her victory.

“If the Alaska Native community raises its decibel level on matters from subsistence to civil rights, that would register with Sen. Murkowski,” said a source familiar with Murkowski’s thinking, who requested anonymity to speak freely.

This would be a death knell to us in Alaska. Heather Kendall-Miller, an Alaska Native attorney

Local Alaska tribes and constituents perhaps carry the most weight in shaping Murkowski’s decisions. She’s hearing from them, too.

The leaders of four Alaska tribal councils separately wrote to Murkowski and Sen. Dan Sullivan (R-Alaska) last week, urging them to oppose Kavanaugh. Letters came from leaders of the Hughes Tribal Council, the Ruby Tribal Council, the Tanana Tribal Council and the Native Village of Venetie Tribal Government.

Late Friday, the leader of the Tlingit and Haida Tribes of Alaska ― which have more than 30,000 tribal citizens ― posted a letter on Facebook on behalf of the tribes urging Murkowski to vote no.

“We are concerned moving his nomination forward due to his unsound views and the potential injury that his misperceptions would wreak upon your Native Alaskan constituents, our Native Hawaiian friends and fellow indigenous peoples,” said tribal President Richard Chalyee Éesh Peterson.

Some Alaska residents came to Capitol Hill on Thursday to protest Kavanaugh and visited Murkowski’s and Sullivan’s offices. One of them, Alaska Native Dorothy Johnson, said putting Kavanaugh on the Supreme Court would put her community’s livelihood at risk.

“If we get our subsistence rights taken away from us, we are going to suffer,” Johnson told news outlet GrayDC. “It’s going to be very hard.”

This story has been updated to include a letter from the Tlingit Haida Tribes of Alaska.