Members of three Native American tribes looking to vote in the 2018 midterms have filed suit against North Dakota's secretary of state for allegedly suppressing their right to vote.

The complaint, filed on behalf of members of the Sioux Spirit Lake, Chippewa, and Cheyenne tribes, alleges that North Dakota's “unplanned, untested, and broken” law requiring voters to present identification at the polls to prove their current residential address poses “a severe impediment” to their constitutional right to vote. Many Native Americans “simply have no residential address because the government has not assigned them one,” according to the lawsuit.

“Because the systems for assigning and verifying residential addresses are deeply flawed and produce conflicting and inaccurate results, and have generated significant confusion, qualified Native American voters face a substantial risk of being denied the right to vote,” the complaint said, noting that affected voters “have already been denied access to the ballot.”

The experiences detailed by the six plaintiffs vary, though mostly revolve around discrepancies with North Dakota's “My Voting Information,” an online tool used by the state to validate residential addresses and plaintiffs' “911” addresses, a state-issued location for mail and emergency services.

One member of the Spirit Lake Tribe claims his absentee ballot was rejected after his address listed on a state-issued ID didn't appear on the online tool. During a 2012 election, two other plaintiffs—Chippewa members living on a reservation—were assigned an address in a different county that doesn't exist in the online tool, and thus have to leave their current county to vote.

Plaintiffs claim these instances violate their First and Fourteenth Amendment rights, and seek injunctive relief to vote in the U.S. midterm elections on Nov. 6. Matthew Campbell, one of the Native American Rights Fund attorneys representing them, said the state “has pushed through a voter identification system that is confusing and in disarray. And people living on reservations are being most affected.”

“Reservation addresses in the state's database are inconsistent, inaccurate, and uncertain. Homes are listed on streets identified as 'unknown' and in towns that are off the reservations. Figuring out the state's peculiar listings for residential addresses on reservations should not be a prerequisite to voting,” Campbell said.

The lawsuit comes amid a contentious midterm election cycle in which Democrats are looking to flip the House and Senate. Sen. Heidi Heitkamp, D-North Dakota, is currently trailing in polls as she seeks re-election against Rep. Kevin Cramer.

Current state law prevents residents from voting without an ID showing their name, residential address and birth date. Robins Kaplan partner Timothy Purdon, another one of the plaintiffs' lawyers, noted that recent investigations suggest this “threatens to disenfranchise not only those who do not have street access to the necessary ID, but those whose IDs contain addresses the state deems 'invalid.'”

“This is extremely problematic as the lawsuit alleges that North Dakota's system for assigning address appears to be incomplete, contradictory, and prone to error on reservations,” he added.

Indeed, one of the plaintiffs in the suit, a Cheyenne, claims she was unable to receive a Tribal ID supplied by a tribe, as she lives on a Sioux reservation without being a member. The plaintiff wants to vote on election day, the complaint says, but “has not identified any way to obtain an identification or supplemental documentation of her residential address that would allow her to vote on Election Day.”

North Dakota Secretary of State Alvin Jaeger's office said they do not comment on pending litigation.

Mark Gaber, senior legal counsel at the Campaign Legal Center who is also representing the plaintiffs, said that “If North Dakota cannot perform the basic governmental function of having a coherent and consistent system of designating street addresses on reservations, then it cannot make having a 'valid' address a precondition to voting.”