Potential fallout from Missourians saying "yes" to medical marijuana at the ballot box.

Voters overwhelmingly passed it in the November mid-terms, but now our state law conflicts with federal law when it comes to using medical marijuana and having a firearm.

Most of us know the supremacy clause of the United States Constitution that says federal law trumps state law. So now that medical marijuana is lawful in Missouri-- what does that mean for gun ownership?

The U.S. Attorney for the Western District of Missouri talks enforcement with us, and gun dealers say there's one pertinent question that makes this easy for him to decipher.

"You're not a lawful user of it (medical marijuana) according to the federal government," explained Nick Newman, owner of Cherokee Firearms.

Business is good at Cherokee-- with all different varieties of guns from which to choose, but only one form to fill out-- with one question in particular.

"Are you an unlawful user of, addicted to, marijuana or any depressant, stimulant, narcotic drug, or any other controlled substance? Warning: The use or possession of marijuana remains unlawful under Federal law, regardless of whether it has been legalized or decriminalized for medical or recreational purposes in the state where you reside."

Newman says that question makes this a black and white issue... no gray.

"So the change again is in the state law, which allows for that, the federal law does not-- and of course we live and breathe for the federal law here... and that's what we have to go by," Newman said.

"Use of marijuana and possession of a firearm is unlawful under Federal law," explained U.S. Attorney Tim Garrison.

Enforcement, though, could be tough. Garrison says in some cases, even perhaps unnecessary.

"We're not terribly interested in an individual who is, for example, using marijuana to combat nausea as a result of their chemo therapy who also happens to own a squirrel rifle in their closet. Most typically, where this statute comes into play in my office is where we have a particularly bad actor who happens to be a drug user and happens to be in possession of a firearm," Garrison said.

A St. Louis representative says he plans to propose a resolution in January that urges Congress to reclassify marijuana or change the part of the federal firearm law to allow gun ownership for medical marijuana users.

Lawmakers would have to re-classify or de-classify it as a schedule one controlled substance.

"Under federal law, marijuana is a schedule one controlled substance which means that under the code of federal regulations there is no acceptable medical use for marijuana, and it has a high risk of abuse," Garrison said. "So even if a state says it will not prosecute someone for possession or use of a certain substance... if it remains a controlled substance, a schedule one controlled substance under federal law... it's still illegal."