Overturning Plessy v. Ferguson and the whole gambit of reactionary Supreme Court decisions from that decision through 1936 is what the whole New Deal legal struggle was over, to create federal legislative supremacy over the judicial and states rights legal structure that blocked progressive legislation.
Much as I disagree with the laws around the drug war, I agree with Justin that it would be a completely constitutional position to have the Supreme Court carve out a states rights position on the issue. The rightwing is pushing forward to carve up such rules to strike down federal antidiscrimination legislation; for progressives to push in the same direction of states rights is absolutely nuts.
As I've repeated, progressives should suck up the judicial deference to Congress and organize to change the fucking law. I know one reason a lot of lefties like the courts is that the deux ex machina of court decisions means they don't have to get their hands dirty with lesser evil decisions in the political realm in order to form the majorities necessary for passage of legislation.
What is amazing on this particular issue is that progressives are winning legislatively on the issue - the very passage of the medical marijauna decision at the state level in California shows that, as do other wins around the country. So the fight just needs to be taken to the national level.
As I said, a lot of lefties don't want to do that, since that involves the political compromises they want to avoid. But playing the judicial game and depending on the courts have their own compromises-- and the historical record shows a much worse record for it.
-- Nathan Newman