U.S. District Judge Reed O'Connor struck down the Biden administration's ATF rule regulating ghost gun kits, finding it unconstitutional on both Second Amendment and vagueness grounds, a ruling that puts the Trump DOJ in the unusual position of defending a Biden-era gun control measure.
O'Connor, a George W. Bush appointee, concluded that the ATF's regulation requiring serial numbers, seller licensing, and background checks for ghost gun kits has no basis in America's historical tradition of personal gunsmithing. The ruling handed a major victory to Defense Distributed and the Second Amendment Foundation, the two plaintiffs who challenged the rule, and reopened a legal fight that has already bounced between the district court, the Fifth Circuit, and the Supreme Court.
The decision lands at a moment when federal courts are reshaping the boundaries of gun regulation across the country. And it sets up a fresh collision at the appellate level, one that could send the ghost gun question back to the Supreme Court on constitutional grounds the justices deliberately left untouched the first time around.
The judge grounded his analysis in the Supreme Court's framework requiring courts to weigh firearms regulations against the nation's historical tradition of gun laws. By that measure, O'Connor found, the ATF rule didn't just lack supporting historical examples. It ran against them.
The Washington Examiner reported that O'Connor wrote directly on the historical record:
"The Final Rule does not merely lack supporting analogues. It contradicts the actual historical tradition of personal gunsmithing."
He went further, citing the deep roots of homemade firearms in American life:
"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 framing matters. O'Connor did not treat the ATF rule as a reasonable regulation that simply went too far. He treated it as a prohibition on conduct the Second Amendment protects, and one drafted so loosely that citizens could not tell what was legal and what wasn't.
The ruling rested on two independent grounds. First, the Second Amendment violation. Second, unconstitutional vagueness, a finding that the regulation's language was too unclear to give ordinary people fair notice of what conduct it banned.
Adam Kraut, executive director of the Second Amendment Foundation, did not hold back about the dual failure. He said the 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."
Kraut added that 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."
That second point, vagueness, carries weight beyond gun policy. When a regulation is so murky that regulated parties cannot comply even if they want to, courts have long held it violates due process. O'Connor found the ghost gun rule crossed that line.
This is not the first time the ghost gun rule has reached a courtroom. The legal battle has been running for years, and the Supreme Court has intervened more than once, but always on procedural or statutory grounds, never on the constitutional merits O'Connor just decided.
In March 2025, the Supreme Court ruled 7-2 that the ATF acted within the scope of its rulemaking authority when it issued the regulation. Justice Neil Gorsuch wrote the majority opinion. But the justices explicitly declined to rule on whether the regulation violated the Second Amendment or was unconstitutionally vague. That left the constitutional questions alive, and O'Connor has now answered them.
Before that, the Supreme Court had twice stepped in to keep the rule enforceable while appeals moved through the courts. In August 2023, the justices voted 5-4 to freeze a lower court ruling that had blocked the regulation. The New York Post reported that Chief Justice John Roberts and Justice Amy Coney Barrett joined the three liberal justices to form the majority in that stay.
Then in October 2023, the Court vacated O'Connor's earlier injunction against the rule. Breitbart noted that the order specifically referenced the case in the Northern District of Texas, and that it marked the second time the justices had intervened to keep the regulation alive.
Each of those earlier rulings addressed enforcement and statutory authority. None reached the Second Amendment question. O'Connor's new ruling does, and that changes the legal terrain entirely.
One of the more unusual dynamics in this case is the Trump administration's role. The Department of Justice, now under Trump, has continued to defend the ATF ghost gun rule in court, placing the administration on the opposite side of gun rights organizations it would ordinarily align with.
Earlier this year, the DOJ filed a motion arguing that the claims brought by Defense Distributed and the Second Amendment Foundation should be dismissed, largely on standing grounds. O'Connor rejected that argument and reached the merits.
The DOJ now faces a choice: appeal O'Connor's ruling to the U.S. Court of Appeals for the Fifth Circuit, or let it stand. An appeal would deepen the administration's commitment to a Biden-era regulation that gun rights groups view as a direct assault on constitutionally protected conduct. Letting the ruling stand would effectively concede the rule's unconstitutionality, a concession with implications for ATF rulemaking authority more broadly.
That tension, a Republican administration defending a Democratic predecessor's gun regulation against its own political allies, underscores how tangled the case has become. Courts have been delivering significant rulings on Biden-era policies with increasing frequency, and this case sits squarely in that pattern.
The Biden administration implemented the ATF rule to address what officials described as a sharp rise in untraceable firearms showing up at crime scenes. The regulation required ghost gun kits, packages of parts that can be assembled into functional firearms without serial numbers, to carry the same markings, licensing, and background check requirements as commercially manufactured guns.
The Washington Free Beacon reported that ghost guns reported to the ATF in criminal investigations increased tenfold from 2016 to 2021, reaching approximately 20,000 cases. AP News reported a similar figure, citing the Justice Department's count of over 19,000 ghost guns seized at crime scenes in 2021 alone.
Those numbers formed the backbone of the government's public safety argument. Solicitor General Elizabeth Prelogar argued in earlier proceedings that "the public-safety interests in reversing the flow of ghost guns to dangerous and otherwise prohibited persons easily outweighs the minor costs that respondents will incur."
But O'Connor's ruling did not turn on policy arguments about crime statistics. It turned on constitutional text and historical tradition. Under the Supreme Court's framework, a regulation that restricts conduct protected by the Second Amendment must find support in the nation's historical tradition of firearms regulation. O'Connor found no such support, and found the opposite.
If the DOJ appeals, the case would move to the Fifth Circuit, which has shown willingness to scrutinize federal regulatory overreach in other contexts. A Fifth Circuit ruling upholding O'Connor could create a direct conflict with the Supreme Court's earlier procedural interventions, potentially forcing the justices to take up the constitutional questions they previously set aside.
The timing adds another layer. The Supreme Court is already preparing to hear cases challenging so-called "assault weapons" bans from Connecticut and Cook County, Illinois, in its next term. Arguments could come as soon as December. A ghost gun case arriving on a constitutional track would join an already crowded Second Amendment docket, one that could reshape the boundaries of permissible firearms regulation for years. Recent high-profile rulings from the Court have already drawn sharp reactions across the political spectrum.
For gun rights organizations, O'Connor's ruling represents a breakthrough. The earlier Supreme Court decision in March 2025, while affirming ATF's statutory authority, left the constitutional door wide open. O'Connor walked through it. Whether the Fifth Circuit and ultimately the Supreme Court follow him will determine whether the federal government can regulate homemade firearms at all, or whether that tradition, as old as the Republic itself, remains beyond Washington's reach.
Federal courts have been active on politically charged questions this year, from immigration policy to state-level legal battles. The ghost gun case now joins that list, with stakes that reach well beyond the kits themselves.
When a regulation fails two separate constitutional tests, the problem isn't the court that struck it down. It's the agency that wrote it.