A federal judge took up the question Monday of whether a Colorado law enacted in 2023 runs afoul of the Constitution by making gun buyers wait three days from the start of a background check before they can take possession of a firearm.
Lawyers opposing the law told the court it lacks any precedent in the country's founding era. "The first 'cooling off'-style waiting period did not come into existence until the 1990s. Thirty years ago. Hardly a tradition," argued the attorney representing the law's challengers. That lawyer went further, contending recent appellate decisions had already sealed the law's fate. "How does Colorado's firearms waiting period law now survive?" he asked. "It doesn't. It simply can't."
The state offered a different reading of both the Constitution and the relevant case law. Assistant Solicitor General Joseph G. Michaels contended that the challengers were effectively asking the court to recognize a constitutional right to acquire a firearm immediately — a concept he said would have been impractical at the nation's founding and is already embedded in federal background-check timelines. Michaels drew a distinction between Colorado's law and the New Mexico statute that had fared poorly in court, noting that Colorado's three-day window runs concurrently with the period federal law already allows for completing background checks — and that the state's aim includes reducing both gun homicides and suicides. "Whether it's under a federal background check or whether it's under Colorado's waiting period law, three days is constitutionally acceptable," Michaels said.
The central legal complication before the court stems from two 10th Circuit decisions that point in opposite directions. A three-judge panel ruled in 2024 on a challenge to Colorado legislation that raised the minimum age for purchasing a firearm from 18 to 21; the panel, comprising three Democratic appointees, turned away the challengers' bid for an injunction. Writing for the majority, Judge Richard E.N. Federico concluded that an age-based restriction on gun purchases fell outside the Second Amendment's protections, relying in part on a 2008 Supreme Court decision that said nothing in that ruling should be read to undermine "laws imposing conditions and qualifications on the commercial sale of arms."
A different 10th Circuit panel later took up a New Mexico statute mandating a seven-day waiting period — extendable to 20 days when background checks are delayed — a law the panel acknowledged was designed to curb impulsive gun violence and suicides and to address a federal provision allowing dealers to complete sales if a background check runs past three days. That panel's majority concluded, by a 2-1 vote, that a waiting period does not qualify as a "condition and qualification" on commercial gun sales of the kind that falls outside Second Amendment scrutiny, and declared the New Mexico law likely unconstitutional. New Mexico, backed by Colorado, sought to have the full 10th Circuit rehear the matter, but the court's full-time judges turned down that request 10-2.
Senior U.S. District Judge John L. Kane, a Jimmy Carter appointee overseeing the Colorado case, directed both sides ahead of Monday's hearing to grapple with the conflict the 10th Circuit's dueling rulings have created, and separately reiterated his reservations about the practicality of the Supreme Court's history-based framework for evaluating Second Amendment claims. In written remarks, Kane noted his worry "that such an independent analysis could lead to inconsistent holdings, as the parties could craft distinct records and present varying arguments in different cases."
Kane will issue a written decision. How he resolves the tension between the circuit's competing precedents — and whether either side will appeal — remains to be determined.