Austin Ashlock aashlock@argusleader.com

South Dakota officially has a challenge to the same-sex marriage ban.

Nancy and Jennie Rosenbrahn and five other South Dakota couples filed a lawsuit with the U.S. District Court just before 5 p.m. Thursday that seeks recognition of same-sex marriage in South Dakota, their lawyer Joshua Newville said.

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"With the filing of this lawsuit, South Dakota will join the many other states in the nation who are engaged in a historic and very important discussion about it what means to treat each other equally under the law," Newville said.

The plaintiffs involved in the case refused statements Thursday.

On Wednesday, Nancy Rosenbrahn said regardless of how the lawsuit ends, their goals have been met.

"We have accomplished what we wanted to accomplish. The reason we decided to take on South Dakota is to open up these conversations," she said. "And now, because of (the lawsuit) we are giving them an opportunity to talk about their laws."

The lawsuit claims a 1996 state law and subsequent 2006 constitutional amendment making same-sex marriage illegal in South Dakota violate the U.S. Constitution. The complaint also challenges the state's right to not recognize same-sex marriages carried out outside of the state.

The five other couples involved in the lawsuit include: Jeremy Coller and Clay Schweitzer, Lynn and Monica Serling-Swank, Krystal Cosby and Kaitlynn Hoerner, Barbara and Ashley Wright, and Greg Kniffen and Mark Church.

Aside from Cosby and Hoerner, each couple involved in the lawsuit has been legally married outside of South Dakota.

Defendants named in the lawsuit include: Gov. Dennis Daugaard, Attorney General Marty Jackley, Secretary of Health Doneen Hollingsworth, Secretary of Public Safety Trevor Jones, Pennington County Register of Deeds Donna Mayer, and Brown County Register of Deeds Carol Sherman.

With Thursday's challenge, South Dakota joins 29 other states with active lawsuits against the same-sex marriage ban.

Carl Tobias, law professor at the University of Richmond, has been closely following the string of same-sex marriage challenges and said similar cases have been winning elsewhere in the country.

"I expect (the court) to see it through," he said. "But, we will just have to see who gets the case and how quickly it moves."

North Dakota is now the sole state with a same-sex marriage ban that's yet to see a challenge to its law. A lawsuit challenging Montana's ban was filed Wednesday.

"Like the rest of the country, South Dakota is a state full of loving and committed couples, many of whom are same-sex, who desire to be united in marriage," Newville said.

Newville is a Minneapolis-based lawyer with Madia Law and graduated from the University of Minnesota Law School in 2012.

Based on similar cases deeming bans unconstitutional, Tobias said most judges who receive the case simply analyze the law, skipping over evidence.

"Some cases take evidence, but a lot of judges just address the legal issue," he said. "They want to determine if this violates the Fourteenth Amendment or equal protection."

Jackley told the Argus Leader Wednesday that he would defend the state constitution when it comes to the issue of same-sex marriage.

However, Tobias said that isn't quite so simple.

"Most attorney generals in these cases are trying to show that there is a valid basis, and so far the judges haven't bought that," he said. "If struck down, however, most make appeals."