Gov. Jay Nixon says Missouri voters should have another chance to vote on gay marriage and that he would vote to allow such unions.
The Democratic governor said Thursday he supports repealing an amendment to the Missouri Constitution that defines marriage as a union between a man and a woman.
Missouri in 2004 became the first state to enact a constitutional prohibition on same-sex marriage. It was approved by 70 percent of voters.
Nixon's announcement comes one day after the American Civil Liberties Union filed a lawsuit seeking to force Missouri to recognize the out-of-state marriages of several same-sex couples.
Nixon has also called for passage this year of legislation barring discrimination based on sexual orientation. He also directed state tax officials to accept joint returns from legally married gay couples.