100 years ago, we thought a constitutional amendment was necessary to ban a substance within a state.
It's already been tried and failed with medical marijuana, Gonzales v. Raich (2005). And, for that matter, commercial wheat farming, in Wickard v. Filburn (1942).
It's unlikely recreational marijuana would result in a different result.
This may leave the Feds needing to say, "We can't prohibit it. That's outside the powers given to the Federal government. But we can tax it, and tax it highly enough that nobody can afford it..."
If the founding fathers had intended for an unrestricted commerce clause, they wouldn't have bothered with the 10th amendment or enumerating the other powers. The constitution is a whitelist.
> It's unlikely recreational marijuana would result in a different result.
I dunno, with originalists like Thomas & (hopefully) Gorsuch it's certainly possible. Bad precedent needn't necessarily stand, after all.
Compared to Raich (2005), even if Gorsuch flipped from the way Scalia went you need another vote; Thomas was on the Court then so is no change.
Ah, somebody already mentioned Wickard.
The Supreme Court ruling on that case was a huge blow to both marijuana legalization efforts and gun rights.