South Dakota Attorney General Marty Jackley has said he will defend the state's ban on gay marriage in an upcoming challenge.

Nancy Robrahn, 68, and Jennie Rosenkranz, 72, of Rapid City married Saturday in Minnesota after they were denied a South Dakota marriage license by the Pennington County clerk.

The women, together 27 years, plan on joining two other couples in challenging the state's marriage ban approved by lawmakers in 1996 and reinforced a decade later with a voter-approved constitutional amendment defining marriage as a heterosexual union.

The two other couples are two men who plan to marry soon in Iowa and a lesbian couple who married in Connecticut.

Attorney General Marty Jackley, a Republican, said he will defend the ban in court.

“It is the statutory responsibility of the attorney general to defend both our state constitution and statutory laws, which I intend to do if a lawsuit is filed,” Jackley told the AP.

Jackley added that he believes the issue should be settled at the ballot box “and not from a court system or a court challenge.”

According to the Human Rights Campaign (HRC), only four states remain without an active lawsuit challenging marriage equality bans. Once the South Dakota case is filed, the remaining states will be Alaska, Montana and North Dakota.