Really?
Seems to me that the unbridled cultivation and free intrastate distribution of medical marijuana would have a major negative impact on the interstate commerce of Marinol and every other FDA approved drug for those illnesses.
Yes, and if there are some women who open their legs to every man who walks by, prostitutes will suffer, and interstate commerce is affected. That doesn't give the federal government the right to regulate loose women's naughty bits.
Anything can affect interstate commerce in some trivial way.
Medical marijuana does not affect it to a non-trivial degree; hence it does not fall under federal jurisdiction.
See UNITED STATES v. MORRISON et al., the very recent case in which SCOTUS rejects the "Violence Against Women Act," on the grounds that rape doesn't affect interstate commerce to enough of a degree.
FDR would be proud. Tell me, is there any activity that you don't believe has an "impact" on interstate commerce? After all, if X is any noncommercial intrastate activity, it can be prohibited, because if I don't do X, I might instead do some other activity that does involve interstate commerce, right?