[CommerceComet]

Maybe if the drugs cross state borders, it becomes a federal offense. (interstate commerce).

Under the idea of interstate commerce, wouldn't merely placing a telephone call as part of the crime make it a federal offense?

[Cowboy Bob]

If you make a buy over the phone, then yes.

Please see Wickard vs. Filburn (1942), where the Federal government made a power grab under the commerce clause.