U.S. District Judge Reed O'Connor has ruled that the Biden administration's ATF regulation on ghost gun kits violates the Second Amendment and is unconstitutionally vague, a decision that could reshape the legal battle over homemade firearms.
O'Connor, a George W. Bush appointee, found that the Bureau of Alcohol, Tobacco, Firearms and Explosives overstepped when it required ghost gun kits to carry serial numbers, mandated that sellers obtain federal licenses, and imposed background checks on buyers. The rule, implemented during the Biden administration, treated unfinished gun parts the same as completed firearms. O'Connor rejected that framework on two independent grounds: it infringes on the constitutional right to bear arms, and it is written so poorly that ordinary people cannot determine what conduct it prohibits.
The ruling marks the latest chapter in a legal saga that has already reached the Supreme Court, and may end up there again. It also puts the Trump administration in an awkward position, since the Department of Justice has continued defending the Biden-era regulation in court even as gun rights organizations allied with conservative voters challenged it.
The judge leaned heavily on recent Supreme Court precedent requiring courts to weigh American historical tradition when evaluating the constitutionality of firearms regulations. That standard, rather than the interest-balancing tests favored by progressive legal scholars, demands that the government identify historical analogues for any restriction it seeks to impose. O'Connor concluded the ATF rule fails that test entirely.
In his opinion, O'Connor wrote:
"The Final Rule does not merely lack supporting analogues. It contradicts the actual historical tradition of personal gunsmithing."
He went further, noting that building one's own firearms is not some modern loophole but a practice woven into the country's founding. Americans made their own weapons during the Revolution and continued doing so for centuries afterward, largely without government interference.
"Self-manufacture of firearms in America was common and indeed foundational to establishing our Nation. Americans throughout our history have continued to build their own arms and that 'right [has] remained unregulated throughout [much of] American history.'"
That historical record did not merely undercut the ATF's position. It pointed in the opposite direction, toward a tradition of individual gunsmithing that the Biden-era rule sought to regulate out of existence.
Beyond the Second Amendment question, O'Connor found the regulation unconstitutionally vague. That is a separate constitutional defect rooted in the Due Process Clause: if a law or rule is written so ambiguously that a reasonable person cannot tell what it requires, it cannot stand.
Adam Kraut, executive director of the Second Amendment Foundation, one of the two plaintiff organizations in the case, seized on that dual failure. SAF and Defense Distributed brought the challenge together, arguing the rule both violated gun rights and left law-abiding citizens guessing about what was legal.
Kraut did not hold back in a statement after the ruling:
"This rule was such a mess that it not only violated the Second Amendment but was so terribly drafted that it managed to be ruled unconstitutionally vague."
He added that the court recognized the rule's chilling effect on lawful behavior, a particularly damaging finding for any regulation that touches constitutional rights. When people cannot figure out what the government permits, they stop exercising their rights altogether. That, Kraut argued, was the practical consequence of the ATF's drafting.
"The Court rightly held that the Biden ATF's rule not only sought to outright prohibit Second Amendment protected conduct but was written in such a vague and vaporous manner as to chill that protected conduct by making it impossible to even know what was legal and what wasn't."
Federal courts across the country have wrestled with questions about how far executive agencies can stretch their authority, a pattern visible in recent rulings where judges have checked politically motivated regulatory actions.
This is not the first time O'Connor has ruled against the ghost gun regulation. He previously blocked the rule, only to see the Supreme Court intervene. In a 5-4 decision, the high court froze O'Connor's earlier injunction and allowed the ATF rule to remain in effect while legal challenges continued. Chief Justice John Roberts and Justice Amy Coney Barrett joined the three liberal justices in that narrow majority.
The Supreme Court later vacated O'Connor's earlier injunction altogether, keeping the regulation alive. But neither of those procedural moves addressed whether the rule was constitutional. The justices were deciding only whether the ATF had the statutory authority to issue the regulation in the first place, a narrower question about agency power, not individual rights.
Then in March 2025, the Supreme Court ruled 7-2 that the ATF was acting within the scope of its rulemaking authority when it created the ghost gun regulation. Justice Neil Gorsuch authored the majority opinion. But again, the justices explicitly declined to rule on whether the regulation violated the Constitution. That left the door wide open for exactly the challenge O'Connor has now decided.
The distinction matters. Saying an agency had the power to write a rule is not the same as saying the rule itself passes constitutional muster. The March 2025 ruling settled the first question. O'Connor's new decision tackles the second, and reaches the opposite conclusion.
One of the more unusual dimensions of this case is the Trump administration's role. Despite the president's close alignment with gun rights organizations, his Department of Justice continued to defend the Biden-era ATF regulation in court. Earlier in 2026, DOJ filed a motion arguing that the court should dismiss the claims brought by Defense Distributed and the Second Amendment Foundation, largely on the ground that the plaintiffs lacked standing to sue.
O'Connor rejected that argument and ruled on the merits. The result is a loss not just for the Biden-era policy but for the current administration's legal team, which chose to stand behind a regulation that a federal judge has now declared unconstitutional on two separate grounds.
The case represents one of the rare instances where the Trump administration has found itself on the opposite side of gun rights groups in a legal fight. Whether DOJ will appeal O'Connor's ruling to the U.S. Court of Appeals for the Fifth Circuit remains an open question. If it does, the case could eventually return to the Supreme Court, this time on constitutional grounds the justices have not yet addressed.
Other recent federal court rulings have gone in the administration's favor on politically charged matters, making this defeat all the more conspicuous.
The Biden administration justified the regulation by pointing to a sharp rise in ghost guns recovered at crime scenes. Law enforcement agencies across the country seized more than 19,000 ghost guns at crime scenes in 2021, a more than tenfold increase over just five years. Submissions of ghost guns to the ATF rose from roughly 1,600 in 2017 to over 19,000 by 2021, National Review reported.
Supporters of the regulation, including gun control groups and the Biden-era Solicitor General, argued that without serial numbers and background checks, untraceable firearms would continue flowing to people legally barred from owning guns. The administration previously warned that allowing O'Connor's earlier ruling to stand would enable an "irreversible flow" of ghost guns into communities, as the Washington Free Beacon reported.
But O'Connor's ruling reframes the question. The issue is not whether ghost guns pose a law enforcement challenge, it is whether the federal government can address that challenge by regulating a practice with deep roots in American history, using a rule so ambiguous that citizens cannot comply with confidence. On both counts, the judge said no.
The ghost gun ruling arrives as the Supreme Court prepares to take up an even larger Second Amendment dispute. The justices are set to hear challenges to so-called "assault weapons" bans in Connecticut and Cook County, Illinois, during their next term. Arguments have not yet been scheduled but could take place as soon as December.
That case will test whether the same historical-tradition framework O'Connor applied to ghost guns can be used to strike down bans on entire categories of commonly owned firearms. The outcome could affect millions of gun owners and reshape firearms law nationwide.
Courts at every level continue to grapple with how far government authority extends, whether the subject is high-profile legal disputes involving public figures or foundational questions about constitutional rights. The ghost gun case sits squarely in the latter category.
When a federal judge can strike down a regulation on two independent constitutional grounds, and cite the nation's own history to do it, the rule was never on solid footing. The Biden administration built it anyway, and now taxpayers are funding its defense in court under a new president who never asked for the fight.