Justice Thomas, dissenting.
Respondents Diane Monson and Angel Raich use marijuana that has never been bought or sold, that has never crossed state lines, and that has had no demonstrable effect on the national market for marijuana. If Congress can regulate this under the Commerce Clause, then it can regulate virtually anything–and the Federal Government is no longer one of limited and enumerated powers.
I Respondents’ local cultivation and consumption of marijuana is not “Commerce … among the several States.” U.S. Const., Art. I, §8, cl. 3. By holding that Congress may regulate activity that is neither interstate nor commerce under the Interstate Commerce Clause, the Court abandons any attempt to enforce the Constitution’s limits on federal power. The majority supports this conclusion by invoking, without explanation, the Necessary and Proper Clause. Regulating respondents’ conduct, however, is not “necessary and proper for carrying into Execution” Congress’ restrictions on the interstate drug trade. Art. I, §8, cl. 18.
Thus, neither the Commerce Clause nor the Necessary and Proper Clause grants Congress the power to regulate respondents’ conduct.
http://www.law.cornell.edu/supct/html/03-1454.ZD1.html
However, opiates largely require importation and processing, and meth requires manufacture with a wide range of chemicals, and both would be well outside the scope of Thomas's dissent in Raich, IMO.