South Dakota's gay marriage ban is poised to become the next such law to be challenged in court.
The plaintiffs will be a lesbian couple who have been together for 27 years.
Nancy Robrahn and Jennie Rosenkranz, who have four children and six grandchildren, will travel of Minneapolis, Minnesota, this weekend to get married.
They will be married by Minneapolis Mayor Betsy Hodge at the Community of Christ Church.
The couple will then return home and join two other couples in filing a lawsuit challenging South Dakota's 2006 constitutional same-sex marriage ban.
'We already consider ourselves married - this is a re-dedication of that marriage,' Robrahn, 68, said in a statement. 'We hope to see the day when couples like us don’t have to travel out of South Dakota to marry.'
She points out that by getting married in Minnesota, there are many federal protections that will become available to the couple.
'We are approaching the time when end of life decisions and plans need to be made,' Robrahn said.
The lawsuit will be filed in federal court and will seek to overturn South Dakota’s same-sex marriage ban and to require the state to recognize marriages performed out of state.
'South Dakota has failed to treat all of its citizens with the dignity and respect deserved by all people. With the filing of this lawsuit, we will lead South Dakota down a better path,' said attorney Joshua Newville of Minneapolis-based Madia Law LLC which is representing the three couples.