Colorado’s House Republicans are asking the federal government to review the constitutionality of a recently signed law requiring individuals to take a safety training course through Colorado Parks and Wildlife to be eligible to buy or sell semiautomatic rifles, shotguns, or handguns with detachable magazines.

While Gov. Jared Polis signed the bill into law last week, it will not take effect until Aug. 1, 2026.

Supporters have argued the bill would help prevent mass shootings, pointing to attacks in Colorado at the Aurora movie theater, Boulder King Soopers and Club Q in Colorado Springs, which they said were all carried out using semiautomatic weapons with detachable magazines.

Opponents, including the gun rights advocacy group Rocky Mountain Gun Owners, have countered that the bill further chips away at the Second Amendment rights of law-abiding citizens and forces the wildlife agency to handle responsibilities outside of its scope — without accomplishing its purported goal to stop violence.

Other critics have argued that that the slew of firearms restrictions approved by the Democratic-controlled legislature haven’t stopped gun violence, while at the same time making it difficult for Coloradans to defend themselves against criminals who don’t adhere to state gun laws.

In a letter sent to U.S. Attorney General Pam Bondi on April 14, the caucus called Senate Bill 003 “one of the most extreme” gun laws in the country and urged her to make challenging the new law a priority.

“Because of the unconstitutionality, as well as the imminent risk posed to Coloradans by eliminating their right to firearms as a means of self-defense, it is our belief that the passage of SB25-003 constitutes an emergency for our state and calls for federal investigation,” the letter stated.

During a press conference at the Capitol on Wednesday, Rep. Max Brooks, R-Castle Rock, said he and Senate Minority Leader Paul Lundeen of Colorado Springs also drafted a resolution asking state courts to review the bill’s constitutionality. They said Democratic leadership in the Senate “refused” to hear it on the floor.

Those allegations are untrue, according to Senate President James Coleman, who told Colorado Politics that he Lundeen mutually agreed not to hear the resolution because the gun bill already passed.

Brooks defended the House’s efforts to invite federal intervention into a state policy. 

“We owe it to the people of Colorado to ensure that the laws we pass are constitutional,” Brooks said. “This is not a partisan issue; it’s a fundamental responsibility and a legislative process. When we pass laws that touch on constitutional rights, or in this case, freely trample upon them, we should welcome judicial review.”

He added: “But instead of allowing that, Democrats refused to even introduce the resolution. They refuse to allow a single conversation about whether this law would hold up under the Colorado Constitution.”

Brooks said the bill contains vague definitions of terms like “standard rate of fire” and contains “procedural hurdles” like training courses, eligibility cards and sheriff’s approvals.

“All of those create barriers for law-abiding citizens” he said. “It offers exemptions to some groups while denying them to others, raising serious equal protection concerns. Coloradans deserve better. They deserve clarity, they deserve fairness, and they deserve laws that reflect constitutional integrity, not rushed policy that bypasses legal scrutiny and public trust.”

Brooks said the bill also carves out exemptions for members of law enforcement and the military, which he said could pose questions of constitutionality under the Equal Protection Clause.

Rep. Carlos Barron, R-Fort Lupton, said the training course imposes a barrier to low-income Coloradans who may be unable to afford the required training.

“When you increase cost, add bureaucracy and restrict access to lawful self-defense, you are not protecting people, you are punishing the very communities that need support the most,” he said. “We should be removing barriers, not building more. If safety is truly the goal, we must make sure that laws apply fairly, equitably, and constitutionally for every Coloradan, regardless of zip code or income.”

During last week’s bill signing, Polis said he is working with CPW to create a scholarship program for the training course.

At the signing ceremony, Sen. Tom Sullivan, D-Commerce City, one of the bill’s sponsors, said the legislation underwent several changes.

“With the people in this room and legislators who have had the courage to stand up to our opposition, we have been able to add to the safety of each and every Coloradan, especially when it comes to gun violence. There is more to do,” he said. 

 House Minority Leader Rose Pugliese of Colorado Springs said Bondi has not yet responded to the letter. Only the House Republicans — not the Senate Republicans — signed on to it.