The Attorney General in the US state of Kentucky has defended the state’s equal marriage ban, despite his office admitting that overturning it would grant equal legal protections to same-sex couples.

Assistant Attorney General Clay Barkley filed an 18-page request today in federal court asking US District Judge John G Heyburn II to dismiss a challenge to the state’s equal marriage bill.

Barkley’s filing asked Judge Heyburn to dismiss the lawsuit brought by couple Gregory Bourke and Michael De Leon, writing that the men lacked standing to challenge the law.

The couple were married in Canada nine years ago, filed a lawsuit in July in an attempt to forced the state to recognise unions from other states and countries.

A US Supreme Court’s ruling from June against the Defense of Marriage Act (DOMA), was noted as key in their case against the ban.

Their lawsuit is the first to challenge the Kentucky ban since the Supreme Court ruling, and it seeks an injunction to stop state and local officials from enforcing a ban written into the Kentucky constitution in 2004.

The amendment reads: “Only a marriage between one man and one woman shall be valid or recognized as a marriage in Kentucky” and “A marriage between members of the same sex which occurs in another jurisdiction shall be void in Kentucky.”