[JURIST] Six couples filed a federal lawsuit [complaint] Thursday challenging South Dakota’s ban on same-sex marriage [JURIST backgrounder]. The lawsuit, filed in the US District Court for the District of South Dakota [official website], challenges a law [text] passed by the legislature in 1996 and a constitutional amendment [text] approved by voters in 2006. The suit claims that the laws violate the equal protection, due process and right to travel clauses of the Fourteenth Amendment [text] to the US Constitution. According to the complaint, “The marriage bans inflict serious and irreparable harms upon same-sex couples and their children that cannot be explained by reference to any legitimate governmental interest.”

There has been a flurry of litigation surrounding same-sex marriage since the US Supreme Court struck down [JURIST report] Section 3 of the federal Defense of Marriage Act (DOMA) [text; JURIST news archive] last June. Thursday’s lawsuit leaves North Dakota as the only state with a same-sex marriage ban that is not facing a legal challenge. Earlier this week same-sex couples challenged Montana’s same-sex marriage ban, and a federal judge struck down bans in Oregon and Pennsylvania [JURIST reports].