In a controversial move, the Supreme Court sided with the Biden administration this week by allowing a challenged gun rule to remain in effect while its legality is being litigated. 

According to The New York Times, the issue concerns what the Department of Justice (DOJ) deems to be "ghost guns," a term which refers to untraceable firearms that can be assembled at home.

Two Republican-appointed justices side with Democratic appointees

Under a rule promulgated by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) last year, "parts kits that are readily convertible to functional weapons, or functional 'frames' or 'receivers' of weapons, are subject to the same regulations as traditional firearms."

The rule was challenged in court by a gun kit business along with a collection of pro-Second Amendment groups, who maintained that it is unconstitutional.

U.S. District Court Judge Reed O'Connor agreed, stating that "a weapon parts kit is not a firearm" and "that which may become or may be converted to a functional receiver is not itself a receiver."

Yet on Tuesday the Supreme Court reversed O'Connor's order striking down the ATF's rule, saying it can remain in place for now.

That decision saw the Republican-appointed Justice Amy Coney Barrett and Chief Justice John Roberts side with the Democrat-appointed Justices Elena Kagan, Sonia Sotomayor, and Ketanji Brown Jackson.

Solicitor general compares gun kits to IKEA furniture

The ruling was welcomed by the anti-gun group Everytown for Gun Safety, which complained in a statement that "untraceable ghost guns" are "intentionally designed to evade regulation."

Politico noted that lawyers for the plaintiffs and Solicitor General Elizabeth Prelogar clashed over whether the prerequisite parts for creating "ghost guns" should be regarded as firearms.

"Every speaker of English would recognize that a tax on sales of 'bookshelves' applies to IKEA when it sells boxes of parts and the tools and instructions for assembling them into bookshelves," Prelogar was quoted as writing in the government's emergency appeal.

"The court’s insistence on treating guns differently contradicts ordinary usage and makes a mockery of Congress’s careful regulatory scheme," she continued.

Plaintiffs say building guns more similar to making tacos

However, the rule's challengers countered that Prelogar's IKEA furniture example was not analogous to the situation at hand.

"A better analogy would be to a ‘taco kit’ sold as a bundle by a grocery store that includes taco shells, seasoning packets, salsa, and other toppings, along with a slab of raw beef," they wrote.

"No one would call the taco kit a taco. In addition to ‘assembly,’ turning it into one would require cutting or grinding and cooking the meat — and until that was done, it would be nonsensical to treat it as food and the equivalent of a taco," the lawyers added.