Oregon's ban on same-sex marriages was struck down Monday by U.S. District Judge Michael McShane, who ruled that the prohibition violated the federal constitutional rights of gays and lesbians.

Jubilant couples who anticipated a favorable decision from the judge began the rush to officially wed at locations around the state. McShane allowed his order to take immediate effect.

"Because Oregon's marriage laws discriminate on the basis of sexual orientationwithout a rational relationship to any legitimate government interest," McShane wrote in his decision, "the laws violate the Equal Protection Clause of the Fourteenth Amendmenfto the United States Constitution."

Oregon becomes the seventh state where a federal judge has struck down a gay marriage ban since the U.S. Supreme Court last year invalidated key sections of the federal Defense of Marriage Act.

Unlike in the other states — Idaho, Utah, Michigan, Virginia, Oklahoma and Texas — there was no one with the immediate standing to appeal the decision.

The plaintiffs in the Oregon case as well as the defendants, chiefly represented by Attorney General Ellen Rosenblum, urged McShane to strike down Oregon's ban.  They said it violated equal protections for gay and lesbian couples.

The 9th U.S. Circuit Court of Appeals rejected a last-minute attempt by the National Organization for Marriage to halt McShane's ruling. NOM, an anti-gay marriage group,  said it wanted time to appeal McShane's refusal to allow NOM to intervene in the case.

Rosenblum and the plaintiffs in the Oregon case urged the 9th Circuit to deny NOM's motion for a stay.

Backers of gay marriage have been gathering signatures to qualify a measure for the November ballot that would remove the state constitutional provision limiting marriage to one man and one woman. That provision was approved by voters in 2004.

Backers of the gay marriage initiative have said that they planned to drop their measure if they received a favorable ruling from McShane.

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— Jeff Mapes