Six couples filed a federal lawsuit on Thursday, seeking to block South Dakota's gay marriage ban and leaving North Dakota as the only state in the country with an unchallenged law prohibiting same-sex weddings.
The lawsuit, filed in US district court in Sioux Falls, challenges a 1996 law passed by the legislature and a voter-approved 2006 constitutional amendment banning gay marriage, which means such cases are now pending in 30 states with gay marriage bans. The lawsuit also challenges a US provision allowing states not to recognise same-sex marriages performed elsewhere.
In 19 states and the District of Columbia gay couples already can wed,with Oregon and Pennsylvania becoming the latest to join the list this week when federal judges struck down their bans and officials decided not to appeal.
South Dakota attorney general Marty Jackley has said he is obligated by law to defend both the state constitution and state statutes.