Portland, Ore. ? The Oregon Supreme Court on Thursday 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 banned gay marriage. It also noted that Oregon voters approved a constitutional amendment in 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, Democratic Gov. Ted Kulongoski said he would 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 in March 2004, 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 also was shut down by the courts, and those marriages were likewise declared invalid, though a constitutional challenge to California’s law against gay marriage is pending.

Portland writer Rodger Larson says Thursday's court ruling voiding the nearly 3,000 same-sex marriages sanctioned by Multnomah County last year was like

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 May.