As cannabis legalization ripples across the nation, state governments have varied in their responses to a federal law that makes it illegal to possess both a federally-banned substance like cannabis and a legal firearm.

While the federal government has been generally tolerant of state experimentation with cannabis legalization, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) has made it clear it will not tolerate mixing cannabis and guns. Thus, firearms dealers will have to abide by the ATF’s rules by denying medical cannabis card holders and anyone convicted of illegal cannabis possession the right to purchase guns. This raised the question: How can firearms dealers obtain medical cannabis information?

The enforcement of this law creates an absurd policy issue as states must register medical cannabis patient data but not recreational marijuana consumer data. As a result, medical cannabis patients are denied gun rights because the state keeps a registry that shows up when firearm background checks are conducted. Recreational users, however, are not required to register to purchase retail cannabis and are therefore untracked. The contradiction is blatant and damaging to medical patients, especially for those using the non-psychoactive CBD compound found in cannabis products that are commonly used to mitigate epileptic seizures.

While states cannot reverse federal government policy, they have a spectrum upon which they can enforce it. On the more restrictive end of the spectrum, states could require medical cannabis users to surrender all of the guns they currently own as well as forbidding future purchases. Some local governments, like Honolulu, have unsuccessfully attempted this. On the other end of the spectrum, Pennsylvania has crafted an innovative approach centered around database sharing. The state’s Department of Health decided it will no longer share the medical marijuana registry with the state’s law enforcement database, JNET. The practical outcome of this policy is that background checks done by firearms dealers will not identify whether or not the person is a medical marijuana card holder, effectively bypassing the restriction.

The Pennsylvania state police website maintains that it is illegal for citizens to possess both a medical marijuana card and a firearm, meaning that the underlying legal structure has not changed. Pennsylvania’s health agency has simply ceased reporting the marijuana registry to the JNET database, making enforcement of the law much more difficult. Medical patients are still required to have a physical card that law enforcement and firearms dealers could ask for that would invalidate the purchase or possession of a firearm, but no law requires that the card be carried at all times nor that firearms dealers ask for that card at the time of purchase. Pennsylvania is the first state to take this step and could represent a model for other states to follow since there is no explicit legal mandate from the federal government forcing states to share data between agencies.

In conclusion, it is unfortunate that states feel compelled to interrupt federal enforcement, yet it seems likely that the federal government’s stance will be ruled a constitutional violation at some point given state legalization of cannabis. Until then, states should consider their options immediately, as Pennsylvania has done, since criminal penalties for this violation are heavy. Possessing marijuana and a firearm triggers an automatic federal felony, which restricts gun ownership for life alongside the other serious consequences of carrying a felony. Pennsylvania’s practice of withholding medical marijuana registries from state law enforcement databases may be the most amicable solution to this policy issue until the federal government changes the law.