The right to bear arms is enshrined in the United States constitution. But what about the right to bear arms while experiencing a gentle buzz from cannabis?
Concerned about the potentially lethal mixture of drugs and relaxed firearm laws, the US government is trying to stop gun owners using marijuana for medicinal purposes.
A letter from the Bureau of Alcohol, Tobacco and Firearms circulated this week to gun stores reminded retailers that they are banned from selling guns to anyone who is "an unlawful user of, or addicted to, any controlled substance".
"Any person who uses or is addicted to marijuana, regardless of whether his or her state has passed legislation authorising marijuana use for medicinal purposes, is an unlawful user" and is therefore "prohibited... from possessing firearms or ammunition", the message read. So far 16 states have legalised marijuana for medicinal use.
The letter went down like a lead balloon among libertarian politicians. Some say it represents an assault on both the privacy and the civil liberties of freedom-loving Americans.
"Misguided," said Jon Tester, a Montana Senator. "It is unacceptable that law-abiding citizens would be stripped of their Second Amendment rights simply because they hold a state-issued card authorising the possession and use of marijuana."
Jon Svaren, a Navy veteran who hunts and takes cannabis to ease a bad back, told USA Today that the move "is contrary to everything I've ever fought for".
The loudest members of the US gun lobby, however, the National Rifle Association and Gun Owners of America, are refusing to comment. Some believe the famously Conservative organisations are reluctant to take up an issue that might ally them with pot-smoking liberals.