PORTLAND - A coalition filed a lawsuit Friday that seeks to block same-sex marriages in Multnomah County, three days after officials here sanctioned gay weddings for the first time in Oregon history.

The lawsuit was filed in Multnomah County court by the Defense of Marriage Coalition, which was created after Oregon's most populous county announced Wednesday it would begin issuing marriage licenses to same-sex couples.

The group contends that county commissioners violated the state Public Meetings Law by privately agreeing among themselves to change county policy. The group also argues that Oregon law clearly defines marriage as between a man and a woman.

"We would rather have a debate through the democratic process, but we were not given that choice," said Kelly Clark, the attorney for the coalition.

He said four of the five Multnomah County commissioners who approved same-sex marriages deliberated in secret as a way to avoid a public debate.

"These are not people who are new to government," Clark said. "They know this is not how we do things in Oregon."

Ken Choe, an attorney for the American Civil Liberties Union, said the ACLU will help defend the county against the lawsuit.

Choe said the issue was not the decision-making process - which he said followed the law - but rather fairness to gay couples under the Oregon Constitution.

"Their exclusion from civil marriage causes real harm," Choe said. "This is not an abstract debate."

By closing time Thursday, the county had granted 786 marriage licenses over two days - the overwhelming majority going to gay couples. That's nearly twice the number granted last month on the first two days that San Francisco recognized gay marriage.

"Wooo!" exclaimed Kevin Francis, 33, of Salem, throwing his arms around his partner, Tom Cobb, also 33, as the two were pronounced legally married Thursday.

Francis and Cobb were unable to get a marriage license until Thursday morning, and they immediately went to Keller Auditorium, where the gay rights group Basic Rights Oregon had eight people, including a rabbi and several ministers, performing ceremonies.

"We'd talked about going to San Francisco or Canada to get married, but I wanted to get married in Oregon," Francis said.

The Catholic Archdiocese of Portland has denounced Multnomah County's policy and urged commissioners to reconsider.

"The action taken by Multnomah County is a serious affront to the well-being of marriage in our society. Catholics support the respect for all persons, and protection of the institution of marriage," Archbishop John G. Vlazny said in a prepared statement.

Meanwhile, other counties around Oregon were examining the issue and deciding whether to issue licenses, but none had yet joined Multnomah County, said Philip Bransford, spokesman for the Association of Oregon Counties.

In Medford, Central Point farmers Stephen and George Miller-Zauner, who share the same last name, have taken out an application for a marriage license, and Jackson County Clerk Kathy Beckett said she will decide this week whether to issue one.

"We've always determined marriage was between a man and a woman, but things are changing," Beckett told the Mail Tribune newspaper. "It's wide-open with Multnomah County issuing marriage licenses. It's brought the whole issue to the surface and I need to get with the county counsel and review statute and case law."

Democratic Gov. Ted Kulongoski warned the marriages may not be legal, saying the 19th century lawmakers who framed the statute clearly suggested marriage was a union between men and women.

Oregon Attorney General Hardy Myers was expected to issue an opinion on same-sex marriage within the week. It is not legally binding but will point the way for future state policy.