The national debate over same-sex marriage erupted from coast to coast Wednesday, as exuberant gay and lesbian couples braved rain and wind to exchange wedding vows in Portland, while the mayors of two New York towns vowed to defy a state attorney general's warning that such marriages are illegal.

Meanwhile, in Washington, D.C., Republican Senate Majority Leader Bill Frist of Tennessee predicted that gay marriages would spread through all 50 states unless Congress approved a constitutional amendment banning such unions.

"It is becoming increasingly clear that Congress must act," Frist said, noting that the Senate would vote this year on such an amendment. "We are gambling with our future if we allow activist judges to redefine marriage for our whole society."

The Los Angeles County Board of Supervisors and the Los Angeles City Council on Wednesday passed resolutions opposing a constitutional amendment to ban same-sex marriages.

The supervisors voted 3-2 in favor of a resolution by Supervisor Zev Yaroslavsky; voting against the resolution were Supervisors Don Knabe and Michael Antonovich. The City Council voted 14-0 in favor of a resolution introduced by Eric Garcetti, Tom LaBonge and Jack Weiss.

Oregon and New York are among 12 states whose laws do not specifically address the issue of same-sex marriage. Thirty-eight states ban the practice outright, but four of them -- California, New Jersey, Vermont and Hawaii -- offer limited privileges to same-sex couples. Only Massachusetts law allows specifically for gay marriages, beginning May 17. Lawmakers in that state will meet next week to consider amending the state constitution in order to ban such unions.

Clashes over same-sex unions have varied from state to state: In New Mexico, a county clerk issued wedding licenses to 26 couples before she was blocked by the state attorney general. In Georgia, black legislators have stalled an effort by other lawmakers to halt gay marriages by passing a state constitutional amendment.

The volatile issue surfaced Wednesday in Portland, where Multnomah County Chairwoman Diane Linn ordered clerks to issue wedding licenses to same-sex couples. Linn said she took the action after a county attorney determined that restricting marriage to the union of a man and a woman discriminated against gay and lesbian couples and violated the state constitution.

Oregon Gov. Ted Kulongoski, a Democrat, said he favored civil unions but questioned the legality of the decision to issue marriage licenses in Multnomah County, one of the state's most liberal and populous areas.

"Reasonable people can differ," he said, "but I think when you read it [the state marriage statute] at the time in history when the statute was written, I think it is clear they were thinking about a man and a woman getting married," the governor said in a statement.

Kulongoski added that it would be up to state Atty. Gen. Hardy Meyers to decide what, if any, enforcement action to take against Multnomah County. A spokesman for Meyers said he expected to issue an opinion in a few days.

As word of Linn's decision spread Tuesday night, hundreds of couples started lining up at the county courthouse, huddling under umbrellas. They poured into the building when it opened Wednesday morning. Hours later, Oregon had its first two same-sex wedded couples.

Mary Li, 40, a county employee, and Rebecca Kennedy, 43, a self-described stay-at-home mom, were the first to exchange vows.

"We are here today to witness the marriage of Becky and Mary," said retired Oregon Supreme Court Justice Betty Roberts, who conducted the ceremony. Kennedy's 9-month-old daughter, Ava, was cradled in a friend's arms nearby as the celebration unfolded.

"I'm beyond excited," said Li, adding that the couple had been together for four years. "I'm nervous too. When you're a couple, you have dreams of getting a house and building a life with your family. It started today. It's a great day."

Stephen Knox, 43, and Eric Warshaw, 40, were next to exchange vows. The Portland-area doctors said they had been together for 10 years. Their three adopted children, ages 3 to 5, attended the ceremony.

"As a child, I always thought I was going to be married, but as I grew up society told me I couldn't," Knox said. "Obviously I can. Eric and I already felt married, but now we have the paper."

Roey Thorpe, executive director of Basic Rights Oregon, a gay advocacy group, predicted there would be hundreds of same-sex marriage ceremonies in Portland over the next few days. Previously, the county had allowed gay and lesbians only to register as domestic partners.

"Remember, some of these couples have been waiting years for this," Thorpe said.