The ruling will be appealed by Attorney General John Suthers' office, which defended the ban. The case is the 16th in a row in which a state ban was voided by a judge following last year's U.S. Supreme Court ruling that struck down the federal Defense of Marriage Act.
"Every time we find the constitution protects individuals, it is a victory for everybody," said John McHugh, who argued the case for the plaintiffs and said they will try to ensure appeals go directly to the Colorado Supreme Court. "We will do everything we can do to fast-track this and get marriage licenses issued in every county in Colorado."
Kris McDaniel-Miccio, one of the 18 plaintiffs in the case and a law professor at the University of Denver, said she had anticipated a favorable ruling but was still ecstatic.
"It's validation," she said. "I have wanted this validation my whole life."
In a separate challenge to a gay marriage ban in Utah, a three-judge panel of the Denver-based 10th U.S. Circuit Court of Appeals found that gay couples have a constitutional right to marry. On Wednesday, Utah Attorney General Sean Reyes' office announced it will appeal that decision directly to the nation's highest court.
The 10th Circuit covers Colorado and five other states. Its gay marriage ruling also is on hold pending appeal.
The Colorado attorney general's office on Wednesday urged a judge in Boulder to forbid the clerk in that county from issuing marriage licenses to same-sex couples.
Boulder County Clerk and Recorder Hillary Hall began issuing the licenses after the 10th Circuit panel ruled two weeks ago, despite the legal stay on that decision. Hall argues the appellate ruling already legalized gay marriage in Colorado.
In a statement released after the Crabtree ruling, Suthers said the issue will remain unsettled until the U.S. Supreme Court weighs in. He and the state's governor, John Hickenlooper, have already asked a federal court to freeze all state-level gay marriage litigation until the U.S. Supreme Court rules on the legality of same-sex marriage ban.
"While the legal debate regarding same-sex marriage continues, and many find the legal process frustrating, adherence to the rule of law will bring about the final resolution with the greatest certainty and legal legitimacy," Suthers said.