HELENA — Montana’s attorney general asked a federal court Thursday to uphold the state’s constitutional same-sex marriage ban in response to a lawsuit that seeks to overturn it.

Republican Attorney General Tim Fox said in documents filed in federal court in Great Falls that the people of Montana spoke when they passed the ban in 2004. The ban says marriage is between a man and woman.

In May, four gay couples filed a federal lawsuit challenging the ban. They allege it denies same-sex couples freedoms and dignity afforded to other Montanans and that it denies them legal protections and benefits that come with marriage.

The plaintiffs, several of whom were married in other states, are Shauna and Nicole Goubeaux; Angie and Tonya Rolando; Ben Milano and Chase Weinhandl; and Sue Hawthorne and Adel Johnson.

Democratic Gov. Steve Bullock has expressed his support for the couples who filed the lawsuit.

State marriage bans have been falling around the country since the U.S. Supreme Court last year struck down part of the federal Defense of Marriage Act.

Same-sex marriage currently is legal in 19 states and the District of Columbia. Bans that have been overturned in some other states continue to make their way through the courts.

Jim Taylor, legal director of Montana’s American Civil Liberties Union, has said the Montana case could take up to a year to resolve — barring any higher court action striking down gay marriage bans.