PORTLAND - Voter approval of a state constitutional amendment to ban gay marriage in Oregon will likely go into effect before the end of the year, despite a court battle that began in March.

The big question now is whether the U.S. Supreme Court will eventually decide the constitutionality of banning gay marriage, attorneys for both sides said Wednesday.

"It's not the same case today it was yesterday," said Kelly Clark, attorney for the Defense of Marriage Coalition, which put Measure 36 on the ballot.

The gay marriage issue was sent to the Oregon Supreme Court earlier this year after Multnomah County commissioners decided that any ban on gay marriage violated the state constitution.

Nearly 3,000 gay and lesbian couples were granted marriage licenses before a judge ordered the county to stop until the Legislature could redraft state law.

But the case was immediately appealed by gay rights groups and the American Civil Liberties Union. Final legal briefs are due by the end of the week and will be argued on Nov. 17 at the Oregon Supreme Court in Salem.

Clark argues the court case is now moot because of voter approval of Measure 36. He said the Defense of Marriage Coalition plans to ask the Oregon Supreme Court to dismiss most of the case.

The ACLU will "vigorously oppose" any motion to dismiss, said Dave Fidanque, executive director of the ACLU Oregon chapter.

The same basic question remains, Fidanque said - "whether it's constitutional to deny rights to homosexual couples."

Gov. Ted Kulongoski agrees the courts must address that basic question.

Kulongoski, a former state Supreme Court justice, said the court could ask Multnomah County Circuit Judge Frank Bearden to review his opinion to see whether he would make any changes after voter approval of the gay marriage ban.

But Kulongoski noted Bearden has already ruled the real issue is not marriage - it is a fundamental question "about equal rights and responsibilities."

"Just passing a measure that marriage is between a man and woman doesn't answer that question," the governor said.

Clark said the amendment to limit marriage to a man and a woman simply clarifies existing law.

"It's not about gays and lesbians," Clark said. "It's about the institution of marriage. The other side hasn't grappled with that political reality ... by recognizing that marriage is sacrosanct."

Fidanque noted the amendment will not take effect until 30 days after approval so there is time for the courts to consider the arguments already posed in the case.

The Oregon Supreme Court could consider civil unions as an alternative, or it could uphold Bearden and send the issue to the Legislature to decide, Fidanque said.

"There are lots of different possibilities about what the courts will do," Fidanque said. "But we're not ready to concede anything at this point in terms of the lawsuit."

Both sides, however, agree the legal battle eventually may work its way to the U.S. Supreme Court.

David Kirp, professor of law and public policy at the University of California at Berkeley, compared the gay marriage battle to the civil rights movement of the 1960s.

"What gay rights attorneys have tried to do is what civil rights attorneys did for blacks in the 1960s, and that is to build up the cases in the system," Kirp said.

He said a challenge to Florida adoption laws may help set the stage for a high court ruling on the constitutionality of gay marriage. Gays and lesbians have argued that Florida law has unfairly prevented them from becoming parents by adoption.

"The kids are so obviously much better off with adoptive parents who love them and care about them than being left to rot in the state system that Florida's basis for prohibiting gay couples from adoption is farcical on its face," Kirp said.

"It's really about the enshrinement of prejudice," he said.