The lawsuit, filed in U.S. District Court in Fargo, challenges both North Dakota's ban on gay marriage and its refusal to recognize the marriages of same-sex couples who legally wed in other states. That means cases are currently pending in all 31 states with gay marriage bans. Judges have overturned several of the bans since the U.S. Supreme Court struck down part of the federal Defense of Marriage Act last year.
A federal judge also struck down Wisconsin's ban on same-sex marriage on Friday, ruling it unconstitutional.
North Dakota's attorney general's office said it had not yet seen the suit and thus could not comment on the specifics.
"Ultimately, only the Supreme Court can determine whether North Dakota's enactment is constitutional or not," Attorney General Wayne Stenehjem said in a statement.
Legal experts said because North Dakota is the last state to face a lawsuit, a federal appeals court that covers the region or even the U.S. Supreme Court could rule on another case first, making the lawsuit largely symbolic given that all states with bans have now been challenged.
"It's symbolic, but sometimes symbolism is important, right? I think it has real, practical, actual effects on people nationwide and in North Dakota," said Carl Tobias, a professor at the University of Richmond School of Law who studies constitutional law.
Dale Carpenter, a constitutional law professor at the University of Minnesota Law School, said it was already likely that the Supreme Court would take up the issue of same-sex marriages again this year, but Friday's lawsuit increases the possibility. Rulings in the 4th Circuit and the 10th Circuit Court of Appeals are expected in the coming months.
"They're not going to just wait around, because it's inevitably coming," he said.
Gay couples already can wed in 19 states and the District of Columbia.
Chris Plante, a spokesman for the National Organization for Marriage, said the series of court rulings since the Supreme Court ruled last summer has created a distorted perception of public sentiment.
"This is not a wave of popular opinion that is being changed by any stretch of the imagination," he said. "This is simply a wave of justices who are legislating from the bench," he said.
Filed by Minneapolis attorney Josh Newville, who is also representing six South Dakota couples in a similar case, the lawsuit claims violations on three issues that are guaranteed in the 14th Amendment to the U.S. Constitution: equal protection, due process and right to travel.
Like the South Dakota lawsuit, the complaint seeks a declaration that the statute and constitutional bans are unconstitutional and asks that the state be prevented from enforcing the ban and be required to issue marriage licenses to same-sex couples and recognize gay marriages from other states. It also seeks reimbursement for lawyers and other costs.
"The state will incur little to no burden in allowing same-sex couples to marry and in recognizing the lawful marriages of same-sex couples from other jurisdictions on the same terms as different-sex couples," it states, while saying the gay couples are subject to "an irreparable denial of their constitutional rights."
Josh Boschee, who became the state's first openly gay legislator in 2012, said he believes North Dakota is much different place than it was 10 years ago when the constitutional amendment was passed by 73 percent of voters. Boschee said Friday's lawsuit illustrates that there are people in North Dakota who share a similar sentiment with the rest of the nation.
"I think it shows that there's agreement in all 50 states that current law is unfair to lesbian and gay families," Boschee said.