The Biden Administration’s gun record has hit another snag.

Last Friday, a three-judge panel on the Eighth Circuit Court of Appeals ruled against the administration’s reclassification of pistol-brace-equipped firearms as unregistered short-barrel rifles. It was just the latest in a series of setbacks for President Joe Biden’s aggressive policy of using federal rulemaking to unilaterally expand gun restrictions. It also extended those court losses to a new federal circuit.

The news casts doubt on Biden’s approach and that of his successor for the Democratic Presidential nomination, as Vice President Kamala Harris previously advocated for an even broader push for executive action on guns. At this point, the more relevant question is less whether Biden or Harris could further push the boundaries of executive gun action and more whether any of the restrictions they’ve already implemented will stand up to constitutional scrutiny.

This became a realistic question in the wake of the Supreme Court’s decision in Cargill v. Garland, where the majority actually struck down a Trump-era restriction. The Court found former President Donald Trump’s attempt to use federal rulemaking to ban bump stocks was unlawful back in June. The Eighth Circuit panel’s ruling is now the first to use that precedent in examining President Biden’s attempt to follow the same path to a ban on a different kind of firearm accessory.

In FRAC v. Garland, the panel directly cited Cargill when deciding whether or not the ATF’s brace rule was ripe for a challenge under the Administrative Procedures Act (APA).

“The Supreme Court clearly treated the ATF interpretive rule as a final agency action because the Court held the ATF exceeded its statutory authority and affirmed the Fifth Circuit’s judgment ‘[T]he Final Rule makes it ‘nigh impossible for a regular citizen to determine what constitutes a braced pistol, and … whether a specified braced pistol requires NFA registration,'” Judge L. Steven Grasz wrote for the majority in FRAC v. Garland. “For those reasons, the Final Rule is arbitrary and capricious.”

The panel came to the same conclusion SCOTUS did: the ATF’s attempts to re-interpret existing federal law and subject a wide swath of gun owners to potential criminal penalties qualify for judicial review. And, ultimately, the ATF’s actions were unlawful.

Biden has implemented most of his new restrictions using the same process as the bump stock ban, and they’re vulnerable to the same pitfalls as well.

His administration looked at areas of decades-old federal gun laws it considered to be gray areas and ordered the ATF to reconsider them with stricter interpretations. However, those interpretations were inherently questionable. And, much like with the bump stock ban, they often contradicted what the ATF had previously determined–something the Supreme Court singled out as problematic.

“For many years, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) took the position that semiautomatic rifles equipped with bump stocks were not machineguns under the statute,” Thomas wrote. “On more than 10 separate occasions over several administrations, ATF consistently concluded that rifles equipped with bump stocks cannot ‘automatically’ fire more than one shot ‘by a single function of the trigger.'”

Those questionable reinterpretations and the baggage of the ATF’s past positions jeopardize the Biden-era rules.

Of course, these weaknesses are why most of the Biden rules have been in legal peril basically since they were issued. Most are not even currently enforced, thanks to lower court rulings. In fact, another federal court already invalidated the brace ban.

It’s hard to imagine a scenario where the so-called ghost gun kit ban or the brace ban survives court scrutiny. The ghost gun case is already before the court, and the Eighth Circuit’s ruling provides further motivation for the justices to take it up as well. Or, at the very least, address it more directly in the ghost gun case.

There is one rule that could fare better, though. It doesn’t share the same pitfalls as the other two. And that’s the private gun sales rule.

The thing that may save the gun sales rule is the other aspect of Biden’s legacy that is likely to survive court challenges. That’s the Bipartisan Safer Communities Act, an actual piece of legislation. In addition to a bunch of funding for things like state “red flag” laws or school security, the law expands the background check for 18-to-20-year-olds into nearly a defacto waiting period, and it adds dating partners to the misdemeanor domestic violence gun ban.

Those restrictions have a much better chance of surviving than the ones implemented through pure executive action. But the law also provides some cover for the change to private gun sales regulations via executive rulemaking because it tweaks the underlying statute governing who needs a license to sell guns.

So, unlike the bump stock ban, pistol brace ban, or ghost gun kit ban, the private gun sales rule was preceded by an actual change in the law the ATF interpreted. Of course, that doesn’t necessarily mean that rule will survive. The underlying language change the Biden Administration is relying on to justify restricting private gun sales is modest, and several of the lawmakers who drafted and voted for it have already said the ATF is misinterpreting it.

Even the new gun restrictions in the Bipartisan Safer Communities Act could fail in court. After all, under the Supreme Court’s Bruen standard, the government would have to show the regulations are based in the historical tradition of gun control dating to the Founding Era. That is a stringent test that could trip up any modern gun law.

Still, as the courts work through the myriad of challenges to Biden-era gun restrictions, it’s increasingly likely the private sales rule and Bipartisan Safer Communities Act are the only ones with a realistic chance of surviving.