They already lost this fight in 2005,
Gonzalez vs Raich.
Justice Thomas got that one right:
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.... If the majority is to be taken seriously, the Federal Government may now regulate quilting bees, clothes drives, and potluck suppers throughout the 50 States. This makes a mockery of Madison's assurance to the people of New York that the "powers delegated" to the Federal Government are "few and defined," while those of the States are "numerous and indefinite." The Federalist No. 45, at 313 (J. Madison).I love Thomas. Far and away my favorite justice. Votes correctly even when the immediate results would be to gore his own ox. Much better than Scalia, who tends authoritarian at times, and puts too much into stare decisis. I mean after all, didn’t THOSE decisions overturn decades and in some cases centuries of, if not established legal precedent, at least accepted practice? And NOW we’re supposed to suddenly discover respect for precedent???