It followed more than 20 court victories for supporters of same-sex marriage since the U.S. Supreme Court struck down part of the federal Defense of Marriage Act last year. A federal judge in Louisiana recently upheld that state's ban, but four U.S. appeals courts ruled against state bans.

The issue appears likely to return to the Supreme Court so the nation's highest court can settle whether states can ban gay marriage or that gay and lesbian couples have a fundamental right to marry under the U.S. Constitution. Thirty-two states recently asked the Supreme Court to settle the issue once and for all.