The National Organization for Marriage (NOM) has said that despite a major setback at the U.S. Supreme Court it would continue to fight a federal judge's order making Oregon the 18th state to allow gay couples to marry.

On Wednesday, the Supreme Court declined NOM's request to put on hold a district court's order striking down Oregon's restrictive marriage ban.

(Related: Supreme Court denies NOM's request to stay Oregon gay marriage ruling.)

NOM Chairman John Eastman said in a blog post that his group was “disappointed that the US Supreme Court has declined to issue a stay of a federal judge's order redefining marriage in Oregon.”

Eastman added that NOM would continue to pursue an appeal to intervene in the case.

“That appeal is on track, with briefs due in the Ninth Circuit Court of Appeal in August and September, and oral argument sometime afterwards,” Eastman said. “We will continue to press this case because we believe that the people of Oregon are entitled to a vigorous defense of marriage, and because it is in the public interest to preserve marriage as the union of one man and one woman.”

The setback comes a week after the Maine state ethics board found NOM guilty of violating the state's donor disclosure law and roughly two weeks before NOM holds a major rally outside the Supreme Court in opposition to marriage equality.

(Related: Mike Huckabee to join gay marriage foe NOM at March for Marriage.)