A proposed ballot initiative filed Thursday would redefine same-sex marriages in Colorado as civil unions. A second initiative would allow wedding-related businesses opposed to gay marriage to hire a contractor to serve the couples.

Keeping gay marriage out of Colorado could be difficult, if not impossible, since the U.S. Supreme Court ruled on June 26 that same-sex couples have a right to marry nationwide.

Dave Montez, the executive director of One Colorado, the state’s largest advocacy group for gay rights, said the initiatives are an attempt to undo the Supreme Court decision.

“This initiative is an unnecessary attempt to radically redefine all marriages in Colorado in order to undermine the Supreme Court’s recent decision,” he said. “Even before last week’s Supreme Court decision, the 37 states that already had marriage equality had proven that when loving, committed, gay couples share in the freedom to marry, families are helped and no one is hurt.”

He added, “The freedom to marry is a precious, fundamental right that belongs to all.”

The Colorado legislature approved civil unions in 2013, seven years after the state’s voters approved Amendment 43, which defined marriage as between a man and a woman, with 56 percent in support.

Both ballot questions were filed by Gene Straub and D’Arcy Straub, both of Littleton. D’Arcy Straub is a lawyer. He could not be reached Friday, and his voice message said he was on a mountain-climbing trip. Gene Straub did not immediately return a phone call.

Each measure would need at least 98,492 verified signatures from registered voters to get on the ballot.

State Rep. Dominick Moreno, D-Commerce City, said the point of the gay marriage amendment is moot.

“I think this is more of a political statement than anything,” said Moreno, who serves on the Colorado House Lesbian, Gay, Bisexual and Transgender Caucus. “You can’t override the Supreme Court, especially at the state level.”

Montez called the proposal “mean-spirited, vague and poorly written.”

“Allowing business owners to refuse service to customers whom they dislike, or disapprove, will open a can of worms and make it more difficult to enforce Colorado’s laws that ensure businesses are open to everyone,” he said.

The proposed constitutional amendment states, “A marriage is recognized as a form of religious expression of the people of Colorado that shall not be abridged through the state prescribing or recognizing any law that implicitly or explicitly defines a marriage in opposition or agreement with any particular religious belief.”

Any same-sex couple married before the proposed amendment takes effect or in another state would have their relationship redefined as a civil union, which carries some but not all of the legal rights of marriage.

The proposed change to state law on weddings would require the state to maintain a list of businesses willing to provide services to LGBT couples, so that those opposed could contract with them.

“That doesn’t change anything,” Moreno said. “You’re still treating people differently based on who they are.”

Legislation that resulted from two Denver-area bakers refusing to make cakes — a refusal by a baker to make cake for a gay couple, and another baker who refused to make an anti-gay cake — prompted a bill in the last legislative session to allow bakers or others to refuse service if the request violated their religious values.

The Straubs are scheduled to meet with the state Legislative Council staff on July 16 at the state Capitol to review the language of the proposals.

Joey Bunch: 303-954-1174, jbunch@denverpost.com or twitter.com/joeybunch