If you smoke dope, you can’t own a gun. At least not legally.

Marijuana is now legal for medicinal or recreational purposes in more than half of states. But the federal government still classifies the popular drug as a Schedule 1 narcotic, leaving pot-using gun owners in a bind.

On every background check completed at a federal firearms dealer, prospective buyers are explicitly asked if they are a “user of, or addicted to” the substance. A “yes” answer means the gun seller can’t go through with the transaction. A “no” answer — if false — is a crime punishable as a felony, with up to five years in prison.

Russ Belville, the news director of CannabisRadio.com, tells The Trace it puts marijuana users in a quandary. “Your choice is to perjure yourself or not get your gun,” he says.

In Alaska, Colorado, Oregon, and Washington, adults can legally purchase, own, and consume marijuana. Twenty additional states allow medicinal pot. A slim majority of Americans, 53 percent according to a 2015 Pew study, now support legalization, compared with just 12 percent who did so in 1969. The discrepancy between what a state may permit, and what the federal government explicitly outlaws, has caused well-documented problems for pot sellers, who have trouble simply opening a bank account, and users, who face arrest if they forget they have a joint in a pocket and board an airplane.

Would-be gun owners face a similar dilemma. In 2011, Oregon sheriffs stripped Cynthia Willis of her concealed handgun permit after she obtained a medical marijuana card. Authorities argued that federal law prohibited drug users from purchasing firearms, and therefore Willis could not be issued a permit to carry a firearm. The Oregon Supreme Court ultimately ruled in favor of allowing medical marijuana patients in the state to obtain concealed carry permits.

As Oregon was relaxing its rules, the Bureau of Alcohol, Tobacco, Firearms, and Explosives issued a refusal to step back from standing policy. “There are no exceptions in federal law for marijuana purportedly used for medicinal purposes,” an open letter by a senior agency official to gun dealers reads, “even if such use is sanctioned by state law.” Furthermore, the letter reiterated that gun stores are banned from selling to people if they “have reasonable cause to believe” they use cannabis. (A footnote explains that “the Federal government does not recognize marijuana as a medicine.”)

In December, several medical marijuana patients in Illinois received letters from police informing them that their gun permits were being revoked, even though lawmakers had opted two years earlier to allow legal users to own firearms. The state later informed the patients that the letter was a mistake, and they were allowed to keep their permits.

In practice, the federal prohibition against casual pot users owning guns isn’t often enforced.

“There’s no tracking or database of recreational marijuana users, so unless you go into the gun shop with pot in your hand, or say ‘I just bought some weed and now I’d like a firearm,’ they’re not going to catch you,” Belville says.

But medical marijuana patients face a greater risk of discovery. “In most of the 23 states where it’s legal, registration is mandatory,” Belville says. “Possession of a medical marijuana card can be enough to disqualify you from purchasing a firearm.”

Employees at gun shops contacted by The Trace in the four states where recreational marijuana use is legal say they are not aware of any instances in which a customer got in trouble with federal authorities for lying on a background check application.

But gun owners who use marijuana say they feel the federal ban should be rescinded. They argue that the restriction forces too many otherwise law-abiding people to choose between surrendering their guns in order to obtain the medication they need to combat an illness; keeping their firearms and forgoing the drug; or lying and facing criminal penalties. A spokesperson for the Alaska Cannabis Club says that before the state legalized the substance in 2015, “many people battling illnesses that could have been treated with cannabis were fearful that adding their names to the state’s medical marijuana registry would threaten their right to bear arms, which prevented many from pursuing cannabis as an alternative treatment.”

The discord between state and federal positions has even spurred some conservative lawmakers to speak out in favor of the fight for gun owners to use marijuana.

Alaska Senator Lisa Murkowski, a Republican who opposed the 2014 “legalize it” Ballot Measure 2, now says she nonetheless considers the federal policy on gun ownership and marijuana use to be unfair. On March 2, she sent a letter to Attorney General Loretta Lynch outlining her concerns.

“It is my judgment that denying Americans the personal Second Amendment right to possess firearms as articulated by the Supreme Court in Heller for mere use of marijuana pursuant to state law is arbitrarily overbroad and should be narrowed,” it reads.

She has an unlikely ally in this position in NORML, a pro-marijuana legalization advocacy group. In an end-of-year letter in 2014, NORML’s executive director Allen St. Pierre listed gun rights as one of a number of important issues for adult cannabis consumers.

One constituency reluctant to join the cause: the major gun groups. “I’ve reached out to the [National Rifle Association] on this issue and they’ve shown zero interest, they won’t touch it with a 10-foot pole,” Belville says. “This is speculation, but I think there’s a political bent to it in that NRA supporters generally like the phrase ‘law-abiding gun owner,’ which to them, isn’t pot smokers.”

[Photo: AP Photo/Robert F. Bukaty]