The Nevada Supreme Court has upheld the state’s contentious “ghost gun” ban, reversing a lower court’s ruling that the law banning the sale of unfinished frames and receivers of a firearm was unconstitutionally vague.

The unanimous decision released Thursday comes 13 months after oral arguments were held before the seven-member court, and nearly three years after the initial lawsuit was filed by Polymer80, the prolific Northern Nevada-based firearm manufacturer considered the nation’s largest maker of parts for ghost guns.

The Dayton company’s lawsuit challenged 2021 legislation that banned the possession, purchase, transport or receipt of any unfinished frame or receiver of a firearm, or assembling any firearm not imprinted with a serial number — a law that would effectively shut down a major component of Polymer80’s business in the state. 

Before the law was enacted, Polymer80 sued and won a district court decision concluding key portions of the law related to the manufacture of ghost gun parts was unconstitutionally vague and did not establish clear enforcement guidelines. Lyon County District Court Judge John Schlegelmilch wrote in his ruling that “the most any court can glean from the definition is that it is something less than a firearm and more than a block of raw material.”

Read more: Fate of Nevada’s 2021 ban on ghost gun sales debated before Supreme Court

The court’s Thursday opinion reversed that decision, stating that the language of the law used terms consistent with ordinary meaning, and that “it cannot be said that vagueness pervades their texts.”

“Here, one cannot dance up to the line of criminality and then plead ignorance of terms commonly known in the regulated subject,” the opinion reads.

Gun control advocates say ghost guns and other unfinished firearm frames sold in a kit create a loophole, allowing for individuals who may be prohibited from legally purchasing a firearm to easily purchase and assemble their own stealth firearms without having to undergo a background check and other safeguards required when purchasing a weapon from a federally licensed firearm seller. The company and other supporters say its products are largely purchased by hobbyists, and that attempts to limit their business run afoul of the Second Amendment.

In a Thursday statement, Assemblywoman Sandra Jauregui (D-Las Vegas) — the sponsor of the 2021 legislation — said she was "thankful for the Court’s unanimous ruling to uphold common sense gun safety legislation that will prevent criminals from further endangering our communities."

Though federal law requires completed frames and receivers to be stamped with serial numbers, Polymer80 intentionally designs “unfinished” frames, which are about 80 percent complete. 

According to court documents cited by ProPublica, Polymer80 shipped nearly 52,000 items to customers across the country from January 2019 through October 2020.

At the same time, the number of privately made firearms recovered by law enforcement has increased dramatically — jumping from more than 7,500 nationwide in 2019 to more than 19,000 in 2021, according to the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). ProPublica reported that the “vast majority” of ghost guns recovered are built from Polymer80-produced products.

In Nevada, an investigation by KUNR and APM Reports found that Las Vegas police had seized more than 1,100 unserialized guns since 2020.

Updated on 4/18/24 at 3:34 p.m. to include a statement from Assemblywoman Sandra Jauregui.