SAN FRANCISCO (AP) – The California Supreme Court on July 16 refused to hear a challenge to a vote that could ban same-sex marriages in the state.

The unanimous decision means that, barring further legal action, voters will consider a constitutional amendment in November that would again limit marriage in California to a union between a man and a woman. The court did not give a reason for deciding not to accept the case.

“This was a frivolous lawsuit. It was a desperate attempt to try to keep the voter initiative off the ballot in November,” said Glen Lavy, an attorney with the Alliance Defense Fund representing the measure’s sponsors.

If it passes, the amendment, known as Proposition 8, would overrule the Supreme Court decision that legalized same-sex marriage in the state as of June 16.

Equality California and other gay rights groups issued a statement July 16 saying they were confident that the initiative, similar to same-sex marriage bans enacted in 26 other U.S. states, will fail.

“We’re disappointed, but this ruling does not affect the campaign against Prop. 8 in any way,” the groups said. “We have been focused on continuing the election and moving forward.”

Equality California filed a petition last month arguing that the signature petitions used to put the proposal on the ballot, printed up before the court struck down the state’s marriage laws, were misleading because they stated that the initiative would have no legal or financial effect.

The gay rights group also claimed that Proposition 8 would so drastically alter the promise of equality written into the California Constitution that it was improper to put it before voters as an amendment.

Separately, in the only other U.S. state to allow same-sex marriage, the Massachusetts Senate voted July 15 to repeal a 1913 law used to bar out-of-state couples from marrying in the state. The move to repeal the law, which prohibits couples from obtaining marriage licenses if they could not legally wed in their home states, is driven in part by California’s decision. California does not limit marriage only to state residents.