Wyoming has become the latest state to allow gay marriage, bringing the national wave of expanded rights for same-sex couples to a state where the 1998 beating death of Matthew Shepard still influences national perceptions.

State lawyers filed a legal notice Tuesday morning that said they won't defend a recently overturned Wyoming law that defined marriage as a union between one man and one woman, meaning county clerks can begin to issue marriage licenses to gay couples and the state will recognize same-sex unions performed legally elsewhere.

The change is particularly notable in the state where Shepard, a gay University of Wyoming student was robbed, tied to a fence and viciously beaten 16 years ago in a rural area near Laramie. He died days after the attack on Oct. 12, 1998. The slaying galvanized a national push for gay rights and tough penalties for hate crimes.

A celebration of the long-sought victory -- featuring what could become Wyoming's first same-sex wedding -- was planned for Tuesday evening in Cheyenne.

Wyoming has joined several other politically conservative states in allowing gay marriage after a series of recent court rulings have struck down bans as unconstitutional.

More than 30 states, including Alaska and Arizona, have begun to recognize same-sex unions in changes triggered by a U.S. Supreme Court decision Oct. 6 that refused to hear appeals from states that wanted to defend gay marriage bans.

Gay rights supporters have said bans on same-sex unions are violations of 14th Amendment protections that guarantee equal protection under the law and due process. Opponents have said the issue should be decided by states and voters, not courts.

Rev. Dee Lundberg, pastor of the United Church of Christ in Casper, said she has previously married about 10 couples who have not had their marriages legally recognized by the state.

"For me," Lundberg said, "nothing really changes except when I do a same-sex couple there's the joy of being able to have full legal rights, which I think is a huge issue for emotionally and spiritually just validating families."

Not many same-sex couples were expected to line up right away because Wyoming, the least populated state in the nation, doesn't have a large number of same-sex couples ready to marry.

The Williams Institute, a national think-tank at the UCLA school of law, released a study last month saying there were about 700 same-sex couples in Wyoming and that maybe about 200 would choose to marry within the first year of being able to do so under the changed state status.

The Laramie County Clerk's Office in Cheyenne, the state's biggest city, had just five same-sex couple applications pending.