For several years now, some gun manufacturers have been exploiting a loophole in federal regulations to evade a range of gun control measures by selling firearms in pieces to be assembled later by consumers, including people barred from owning a gun. It's a preposterous situation, and the Biden administration should either address it through stronger regulations under existing congressional authority, or work with Congress on a legislative fix.

The issue centers on so-called ghost guns, which consist of untraceable parts that can be ordered online and then, with a little finishing work, assembled into a working firearm. The gun parts fall outside federal regulation because the Bureau of Alcohol, Tobacco, Firearms and Explosives held that while the core section of a gun — called a receiver or a frame — meets the legal definition of a firearm, an incomplete receiver or frame does not.

In what used to be the purview of gun hobbyists, manufacturers have surfaced that produce receivers and frames that are 80% complete, then sell them to people who finish the production by drilling holes and making other alterations that result in a completed part.

That piece is then the central part of a homemade gun that does not carry a stamped serial number or other traceable identifiers, and is often passed on or sold to people who otherwise would have to clear a background check. It's no surprise that such guns have found their way into the hands of people barred from buying firearms, including those with violent criminal records or mental illnesses or both. In 2019, police nationwide confiscated about 10,000 ghost guns.

Although federal law says that receivers and frames that are "designed to or may readily be converted" into working guns must be regulated, the ATF has said in a series of advisory letters in recent years that the so-called 80% receivers by themselves do not clear that threshold for readiness. Gun control advocates, including Everytown for Gun Safety, argue rightly that experience shows the parts can be, and readily are, finished into working firearms.

The advocates have urged the ATF to reverse its position and treat unfinished receivers and frames the same as finished guns, which would require them to be stamped with a serial number and, in most circumstances, require buyers to pass a background check.

Selling gun parts as a do-it-yourself kit is so close to selling the gun itself that the government should regulate the kits as firearms, including requiring serial numbers and background checks.