But where does federal jurisdiction apply?
Constitutionally (and I know they don't give a rat's rear end about the Constitution anymore), federal jurisdiction applies at ports of entry into the United States and when a good or product is in interstate commerce. How either of these applies in the case at hand, I don't know. But Montana could enact a nullification law similar to what they did a few years ago with regard to firearms.
At any rate, 80 years in prison for medical marijuana is simply malicious prosecution.