OK, let's parse it out. Commerce Clause Long story short, the Commerce Clause acts with the 10th Amendment in a push and pull of debate on what constitutes states' rights and federal dominance to regulate commerce. So as with any debate, one has to go back to the intent of the authors of said clauses to parse out what the law means today. I suspect and would argue that the original authors of the commerce clause wanted to regulate commerce as a form of perserving the delicate balance of the Union. In fact it could be said that the founding fathers wisely wrote limited federal powers to only address such situations where overweening states must be curbed in order to protect and preserve the stability and longevity of the Union as a whole. Allowing one state to overproduce an intoxicating substance that always finds its way into the hands of children of other states would be a direct and provable threat to such stability. Therefore, the FDA is a viable and dominant unit over states when it comes to controlled intoxicating substances. An intoxicated Union is a vulnerable Union. The 10th Amendment would not provide a weighty enough argument for California's illegal drug trade it's currently involved with. I just did. If the fed can and should regulate commerce with respect to mind-altering substances being sold between states and within their borders, then obvious in that implication is the power to prohibit sale of this or that good that might act to destabilize the Union. If you believe the fed should have powers to regulate commerce in order to preserve the Union. And that, I believe, is why they ratified that power: to preserve the Union. It can be argued that the founding fathers granted very little unilateral power to the fed and only then when necessary to clip the wings of overweening states that might threaten the others. I'd say California selling drugs to New York where in both states they are illegal (federally regulated as prohibited commerce), is one state overweening to the detriment of the Union. And this is the case I would frame in general for NY against CA with respect to CA producing an illegal substance in quantities that cannot possibly be consumed by her populace, to the detriment of others states as a whole in the Union. NY being one of those states with proof that said illegal substance made its way from CA across their borders. If the Commerce Clause doesn't cover that, it doesn't cover anything between states. It's a free for all.