Since California passed the first medical marijuana legislation in 1996, 22 other states and the District of Columbia have followed suit. Colorado and Washington legalized recreational use of marijuana in 2012, and last year saw Oregon, Alaska, and D.C. join them. However, under federal law, marijuana remains a Schedule I controlled substance and illegal for any use, whether medical or recreational. As a result, numerous courts across the country have been asked to answer the question of whether federal law making marijuana use or possession illegal preempts state law decriminalizing or legalizing it. In other words, when it comes to marijuana, does federal law trump state law?
Federal preemption occurs when a state law or regulation conflicts with a federal law or regulation. Article VI of the U.S. Constitution, known as the Supremacy Clause, provides that the laws of the United States have supremacy over state constitutions and laws, so that if a state law is in conflict with federal law, federal law trumps. However, what might seem to be a clear case of preemption isn’t always.