Wisconsin voters passed a constitutional amendment banning same-sex marriage on Tuesday, squelching the hopes of gay-rights activists who hoped for their first-ever victory over such a measure in a state vote.

With 50 percent of precincts reporting, 57.5 percent of voters favored the amendment banning state recognition of gay marriage and any type of civil union similar to marriage, according to unofficial returns.

Lorri Pickens, campaign manager for Vote Yes for Marriage, said Wisconsin voters wanted to prevent "activist judges" from potentially legalizing gay marriage.

"People understand that the institution of marriage is an important rockbed and foundation for our communities," Pickens said.

Though similar amendments passed previously in all 20 states to consider them, gay-rights activists had hoped the streak might be broken in Wisconsin.

"We did our best," said Josh Freker, a spokesman for Fair Wisconsin, a group opposing the amendment. "We unfortunately just couldn't move people the way we wanted to."

Freker said this was the first full-fledged campaign to defeat such a measure. And while it ultimately didn't happen, Freker said opponents took some solace in the fact that the debate wasn't as one-sided as it has been in other states.

"We did have a lot of hope," Freker said. "We have seen that the gap has narrowed, and we really did turn out a lot of voters."

Earl Vorpagel, 54, a pastor at Calvary Lutheran Church in Ashwaubenon, favored the marriage amendment for faith-based reasons.

Eight states had ban-gay-marriage amendments on their ballots; South Carolina, Virginia and Tennessee joined Wisconsin in approving them, while results were pending in Arizona, Colorado, Idaho and South Dakota. Similar amendments passed previously in all 20 states to consider them.

"I have no problem with people having equal rights under the law," Vorpagel said. "I just don't want it under the term `marriage."'

Gay marriages have never been allowed in Wisconsin, and voting down the proposed amendment wouldn't necessarily have been a major step toward establishing gay marriages or civil unions. Nevertheless, such a vote would have been considered a victory by gay rights activists.

Bea Browne, a Dane County human services worker, said she voted against the amendment to protect "basic human rights."

"It's a major issue that's on the table today," she said. "Not too long ago in this country, black people and white people weren't allowed to marry."

Supporters said that without an amendment banning gay marriage, an activist judge could make it legal with one ruling.

Betty Wilber, 58, a paper mill worker from Shawano, said her religious beliefs compelled her to vote in favor of the marriage amendment.

"I don't think it was God's right to have two men and two women together," she said.

In another referendum asking voters whether Wisconsin should lift its longstanding ban on the death penalty in certain cases, 53.9 percent of voters said yes in unofficial returns from 50 percent of precincts.

The measure was advisory only, meaning lawmakers and the governor would still have to approve legislation to bring back the penalty which was abolished in the 1850s.