PORTLAND, Ore. – The Oregon Supreme Court yesterday nullified nearly 3,000 marriage licenses issued to gay couples a year ago by Portland’s Multnomah County, saying a county cannot go against state matrimonial law.

“Oregon law currently places the regulation of marriage exclusively within the province of the state’s legislative power,” the high court said in its unanimous ruling.

The court said state law bans gay marriage. It also noted that Oregon voters approved a constitutional amendment last November that even more explicitly prohibits the practice.

Kevin Neely, spokesman for the state attorney general’s office, said the court left the big issue – civil unions for gay couples – for another day. “I suspect the issue will be resolved by either legislation or by additional litigation,” he said.

Legislators had been waiting for the court’s ruling for guidance. On Wednesday, Governor Kulongoski, a Democrat, said he will push for a law allowing gay couples to form civil unions that would give them many of the rights and privileges of marriage.

Multnomah County, which includes much of Portland and is the state’s most populous county, began issuing marriage licenses to gay couples last March, its county commissioners arguing that not doing so would violate the Oregon Constitution.

A judge stopped the practice about six weeks later, but not before nearly 3,000 gay couples had wed.

Similarly, San Francisco started issuing thousands of marriage licenses to gay couples in February 2004. The spree of gay weddings was also shut down by the courts, and those marriages were likewise declared invalid, though a constitutional challenge to California’s law against gay marriage is still pending.

In Oregon, Marte Sheehan, who married Linda Duchek last March, said she was disappointed with the ruling but hopes the Legislature passes a bill allowing civil unions.

“I believe that ultimately the Legislature will do the right thing,” she said.

But the attorney for the Defense of Marriage Coalition, Kelly Clark, noted, “Two West Coast liberal states now, both California and Oregon, have both said that local governments don’t have authority to take the law into their own hands.”

“It certainly sends a signal to the rest of the country,” Mr. Clark said. The ruling came a day after Connecticut lawmakers passed legislation that would make it the second state, after Vermont, to offer civil unions to same-sex couples.

Massachusetts has allowed gay marriage since last May.

In Connecticut, on the other hand, a civil unions bill has raised constitutional questions. With the state on the verge of recognizing same-sex civil unions, questions have surfaced about whether the legislation will affect a lawsuit filed by homosexual couples challenging the constitutionality of Connecticut’s marriage laws.

The state Senate is expected to give final legislative approval to the civil unions bill as early as next week, and Governor Rell, a Republican, has pledged to sign it into law. Before approving the bill Wednesday, the House amended it to define marriage as being between a man and a woman, satisfying concerns Ms. Rell had about the proposal.

Some proponents of same-sex marriage say passage of the legislation could bolster their argument that Connecticut has an unconstitutional and separate system for same-sex couples, thereby stigmatizing gay and lesbian families.