WASHINGTON — U.S. Supreme Court justices Tuesday grappled with whether the Biden administration exceeded its authority when it set regulations for kits that can be assembled into untraceable firearms, and a majority of justices seemed somewhat skeptical the rule was an overreach.

In Garland v. VanDerStok, the nine justices are tasked with determining whether a rule issued by the U.S. Bureau of Alcohol, Tobacco, Firearms, and Explosives in 2022 overstepped in expanding the definition of “firearms” to include “ghost guns” under a federal firearms law.

Ghost guns are firearms without serial numbers and can be easily bought online and quickly assembled in parts, usually through a kit. Law enforcement officials use serial numbers to track guns that are used in crimes.

Arguing on behalf of the Biden administration, U.S. Solicitor General Elizabeth Prelogar told the justices that there has been an “explosion in crimes” with untraceable guns across the U.S.

She added that the federal government has for years required gun manufacturers and sellers to mark firearms with a serial number.

“The industry has followed those conditions without difficulty for more than half a century, and those basic requirements are crucial to solving gun crimes and keeping guns out of the hands of minors, felons and domestic abusers,” Prelogar said.

She said with the kits to make untraceable homemade guns in as little as 15 minutes, those manufacturers “have tried to circumvent those requirements.”

Prelogar said untraceable guns “are attractive to people who can’t lawfully purchase them or who plan to use them in crime.”

Because the ATF saw a spike in crimes committed with those firearms, Prelogar said it promulgated the 2022 rule. The Biden administration said since 2016, it’s seen a tenfold increase in ghost guns.

What the rule does

The regulation does not ban ghost guns, but requires manufacturers of those firearm kits or parts to add a serial number to the products, as well as conduct background checks on potential buyers. The regulation also clarified those kits are considered covered by the 1968 Gun Control Act under the definition of a “firearm.”

The Biden administration is advocating for the Supreme Court to reverse a lower court’s decision that favored gun rights groups and owners that argued the agency exceeded its authority.

Pete Patterson on Tuesday represented those gun rights groups, such as the Firearms Policy Coalition and clients, and argued the ATF expanded the definition of a firearm to “include items that may readily be converted to a frame or receiver.”

A frame or receiver is the primary structure of a firearm that holds the other components that cause the gun to fire.

“Congress decided to regulate only a single part of a firearm, the frame or receiver, and Congress did not alter the common understanding of a frame or receiver,” he said. “ATF has now exceeded its authority by operating outside of the bounds set by Congress.”

The case has already been before the high court on an emergency basis in 2023. The three liberal justices, Sonia Sotomayor, Elena Kagan and Ketanji Brown Jackson, and two conservative justices, Chief Justice John Roberts Jr. and Amy Coney Barrett, allowed the regulation to remain in place while going through legal challenges.

The case is similar to the Supreme Court decision that struck down a Trump-era ban on bump stocks from the ATF, but that was on the grounds of a Second Amendment argument.

Omelets and turkey chili kits

Justice Samuel Alito questioned Prelogar whether the kits were defined as weapons.

“Here’s a blank pad and here’s a pen,” he said. “Is this a grocery list?”

She said it wasn’t because “there are a lot of things you could use those products for to create something other than a grocery list.”

Alito asked her if he had eggs, chopped up ham, peppers and onions, “is that a Western omelet?”

“No, because, again, those items have well known other uses to become something other than an omelet,” Prelogar said. “The key difference here is that these weapon parts kits are designed and intended to be used as instruments of combat, and they have no other conceivable use.”

Barrett asked if her answer would change if “you ordered it from HelloFresh and you got a kit and it was like turkey chili, but all of the ingredients are in the kit?”

Prelogar said it would.

“We are not suggesting that scattered components that might have some entirely separate and distinct function could be aggregated and called a weapon, in the absence of this kind of evidence that that is their intended purpose and function,” she said.

“But if you bought, you know, from Trader Joe’s, some omelet-making kit that had all of the ingredients to make the omelet, and maybe included whatever you would need to start the fire in order to cook the omelet, and had all of that objective indication that that’s what’s being marketed and sold, we would recognize that for what it is,” Prelogar continued.

Roberts asked Patterson what the purpose would be of selling a receiver without a hole in it, meaning the gun is not complete.

Patterson argued that the kits are mainly for gun hobbyists, who would have to drill their own holes to put the product together.

“Some individuals enjoy, like working on their car every weekend, some individuals want to construct their own firearms,” Patterson said.

Roberts seemed skeptical.

“I mean drilling a hole or two, I would think doesn’t give the same sort of reward that you get from working on your car on the weekends,” Roberts said.

Patterson argued that putting together a homemade gun was somewhat difficult, especially if an individual had no experience.

“Even once you have a complete frame, it’s not a trivial matter to put that together,” he said. “There are small parts that have to be put in precise locations.”

No hobbyists

In her rebuttal, Prelogar pushed back on the notion that hobbyists were using those kits, arguing that “if there is a market for these kits, for hobbyists, they can be sold to hobbyists, you just have to comply with the requirements of the Gun Control Act.”

“What the evidence shows is that these guns were being purchased and used in crime. There was a 1,000% increase between 2017 and 2021 in the number of these guns that were recovered as part of criminal investigations,” she said. “The reason why you want a ghost gun is specifically because it’s unserialized and can’t be traced.”