More than 36,000 Native Americans live in North Dakota, constituting the state’s largest minority group as well as a key constituency in the coming midterm elections.

But Rep. Kevin Cramer, a third-term Republican running to unseat Democratic Sen. Heidi Heitkamp, has had run-ins with tribal leaders and is supporting a voter ID law that tribes have said amounts to voter suppression.

Beginning with this election, the state is requiring voters show IDs with their residential address, which many reservations don’t assign them. Instead, many Native Americans use P.O. boxes for their mail.

“This law clearly discriminates against Native Americans in North Dakota,” Standing Rock Sioux Tribe Chairman Mike Faith said in a press release. “Our voices should be heard and they should be heard fairly at the polls just like all other Americans.”

Cramer responded by downplaying the law’s impact.

“I would say if I was the chairman of a tribe and was concerned about this, I’d make sure that my tribal members got an ID from my tribe if they don’t have a driver’s license, and most of them all have a driver’s license as well,” Cramer said in an interview on Valley News Live (KVLY-TV), in a clip circulated by American Bridge, the American Ledger’s parent organization.

This is not the first time Cramer was at odds politically with the state’s five tribes.

In 2013, Cramer was invited to attend a meeting with Native American victim assistance advocates in Bismarck. At the meeting, where they discussed a reauthorization of the Violence Against Women Act that included tribal provisions, Cramer engaged in a heated exchange with members.

Melissa Merrick, Spirit Lake Nation’s victims assistance director, wrote in an account of the meeting that as she was speaking, Cramer cut her off and proceeded to conflate tribes as he peppered her with questions.

After Merrick shared that she was a “survivor” herself, Cramer charged that tribal governments and tribal courts were “dysfunctional,” and that as a “non-Native man,” how could he “get a fair trial on the reservations?”

“Cramer then stated that he wanted to ‘ring the Tribal council’s neck and slam them against the wall,’” Merrick wrote. “This statement was made in front of a room full of people who are working to end violence.”

Cramer, specifically, contested the provision permitting tribal courts limited jurisdiction over non-native people who commit violence against native women. Cramer insisted that Merrick’s reading of the provisions were inaccurate and continued to assert that he couldn’t get a fair trial on a reservation.

Merrick noted that after the exchange, Native American women in the room were visibly upset.

The Spirit Lake Tribal Council had been under fire for how they handled child abuse, but Merrick pushed Cramer to look at the positive work the tribe had been doing.

Cramer later apologized for the altercation but suggested that he didn’t agree entirely with her account of what transpired. When asked why their versions of events didn’t match, Cramer said of Merrick, “Once a victim, always a victim,” according to the Grand Forks Herald.

Last year, Cramer was criticized for not speaking out about a former Spirit Lake Tribe employee who was charged with running a fake adoption scam by highlighting her ties to Cramer.

The woman, Betty Jo Krenz, had appeared in an ad for Cramer’s 2014 campaign highlighting tribal issues. According to an affidavit, Krenz tricked an unsuspecting Oregon woman into paying her thousands of dollars in adoption fees in the hopes of adopting a Native American child.

Cramer was silent, drawing a rebuke from one of Krenz’s victims.

“(Cramer) owes the people of North Dakota an apology for not doing his research on her before aligning himself with her so tightly,” Autym Burke told the High Plains reader. “I have made it clear that he played an intricate role into my faith in her. I believed she was tight with him, she must be okay. I was a fool to believe that, and he is a fool for not stepping up and admitting that a gross error has been made here in his camp.”

And in 2015, Cramer voted twice to recommend the termination of the TIGER Grant program, a federal government program created in 2009 to inject capital into transportation projects around the country. Since Cramer has been in office, two North Dakota projects have received funding, both requested by tribes.

But the voter ID law looms largest over North Dakota politics right now.

On Oct. 9, the Supreme Court, in a 6-2 ruling, declined to overturn a lower-court’s ruling that upheld the law, dealing a blow to the Native Americans fighting it in court and Democrats depending on turnout on reservations.

Julia Krieger, a spokeswoman for the Heitkamp campaign, told The Washington Post recently it was “no secret that North Dakota’s hyperpartisan voter ID laws target student and Native communities because they prefer Heidi in the U.S. Senate.”