KOMO, the ABC affiliate in Seattle, notes the ticklish situation confronting gun owners who might like to try some newly legal marijuana after Washington's state-licensed pot stores begin opening next month: If they do so, they lose their Second Amendment rights. Or so says the Gun Control Act of 1968, which makes it illegal for an "unlawful user" of "any controlled substance" to own a gun. KOMO describes the case of Bobbi Jo Floyd, a Richland resident who was denied a handgun carry permit a few months ago because she was known to be a medical marijuana user. Floyd's experience illustrates what happens when increasingly open cannabis consumption collides with a federal gun restriction that until now has rarely been enforced.

Under federal law, cannabis consumers who possess firearms or ammunition are committing a felony punishable by up to 10 years in prison. Likewise anyone who sells or otherwise transfers a gun to a person he knows or has reasonable cause to believe is a cannabis consumer. There is also a penalty of up to a year in jail for falsely denying, on the form you have to fill out when you buy a gun from a federally licensed dealer, that you are "an unlawful user of, or addicted to, marijuana or any depressant, stimulant, narcotic drug, or any other controlled substance."

Survey data indicate that something like 30 million Americans have consumed marijuana in the last year. Another 9 million or so have illegally consumed other controlled substances (which would include, e.g., taking a painkiller prescribed for a relative). Since people are not always candid when asked about illegal behavior, even in a confidential survey, the true numbers are probably somewhat higher. But conservatively we're talking about at least 15 percent of American adults who are officially disqualified from owning firearms because of the psychoactive substances they consume, with marijuana being by far the most popular.

Usually this rule has no practical effect. You lie on the form (or, in the case of a private transfer, do not fill out a form at all), and who's to know? But occasionally a gun owner's marijuana use (or a marijuana user's gun ownership) comes to the attention of a government official with the power to do something about it. That is what happened to Floyd, who in January applied to the Richland Police Department for a concealed pistol license (CPL). When she filled out the CPL application form, she said she was not "an unlawful user" of marijuana, since Washington has allowed cannabis consumption for medical purposes since 1998 (and for recreational purposes since 2012).

According to a 2011 directive from the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), that was the wrong answer. In a letter to federally licensed firearm dealers, Arthur Herbert, the ATF's assistant director for enforcement programs and services, explained that "any person who uses or is addicted to marijuana, regardless of whether his or her State has passed legislation authorizing marijuana use for medicinal purposes, is an unlawful user of or addicted to a controlled substance."

Still, as long as no one knew that Floyd was a cannabis consumer, that fact would not have stopped her from obtaining a CPL. But someone did know. KOMO reports that a police department employee recognized Floyd, "an outspoken proponent of medical marijuana," and asked her to include a copy of her medical authorization with her application. A couple of weeks later, Floyd received a notice that her application had been rejected. Richland Police Chief Chris Skinner explained in a letter that under federal law Floyd is not even allowed to own a gun, let alone carry one in public. In effect, since it was Floyd's activism that tipped off the police, she lost her Second Amendment rights because she exercised her First Amendment rights. "I was incredibly angry because I was being honest," Floyd tells KOMO. "I had done nothing wrong."

Floyd has been talking to attorneys about challenging Skinner's decision in court. "I'm a Republican," she says, "and I believe in my guns." Medical marijuana patients in neighboring Oregon who were denied carry permits because of their cannabis consumption successfully pursued such a case all the way to the Oregon Supreme Court, which in 2011 ruled that the Gun Control Act does not pre-empt the state law that establishes the requirements for a permit. Those criteria do not include abstaining from marijuana, which Oregon recognizes as a medicine. In 2012 the U.S. Supreme Court declined to hear Jackson County Sheriff Michael Winters' appeal of that decision.

Unlike those Oregon patients, Floyd does not seem to have a very strong basis for challenging the rejection of her CPL application under state law. Washington, like Oregon, is a "shall issue" state, meaning gun owners can obtain carry permits as long as they meet certain objective criteria. But Washington's law, unlike Oregon's, disqualifies any applicant who is "prohibited from possessing a firearm under federal law." Hence the Washington State Department of Licensing lists marijuana use in the last year as grounds for rejecting an application.

What about a Second Amendment challenge? As Brian Doherty reported here a few months ago, a Nevada medical marijuana patient, Rowan Wilson, has so far been unsuccessful in arguing that the ban on gun ownership by cannabis consumers violates the Second Amendment. A federal judge rejected that argument in March, noting that the U.S. Court of Appeals for the 9th Circuit, which includes Washington as well as Nevada, upheld that provision of the Gun Control Act in the 2011 case U.S. v. Dugan. Wilson's lawyer, who intends to appeal, argues that Dugan was weakly reasoned and should be reconsidered.

Meanwhile, Floyd and every other gun-owning cannabis consumer remain felons in the eyes of the federal government. That fact could be a source of serious mischief if Barack Obama or his successor adopts a more confrontational approach to state laws allowing medical or recreational use of marijuana. Even without a shift in federal policy, misguided state officials may force patients to choose between their medicine and their Second Amendment rights, as happened in Illinois this year before a public outcry forced a reversal. In that case, gun rights advocates united with drug policy refomers to oppose a requirement that medical marijuana patients turn in their guns. We will need more such alliances to make sure that the right to keep and bear arms does not disappear in a puff of pot smoke.