Banning Mary Jane
Set that aside. That's not what was at stake in Raich. What was at stake in Raich was really Wickard. Wickard was a ruling issued in 1942, which established very wide standards for "commerce." A farmer who grew his own wheat was held to be bound by laws passed under Congress's powers to regulate commerce between the states.
By saying that activity like that falls into the commerce powers, the Court allowed regulation like OSHA, minimum wage laws, endangered species protections, etc. to go forward. Had the Court held that Congress could not regulate homegrown pot, Congress's power to regulate the treatment of spiders in a single cave in a single state would be cast into question.
I think O'Connor tried to find a distinction between medical and recreational drug use, but clearly couldn't get a majority together.
SCOTUSblog (linked above) notes that this is also a serious blow to the forces of neo-Federalism. They might have wanted to treat this as a states' rights issue, and by strengthening the state, weakening Wickard and the other New Deal rulings which allowed the modern world to flourish. But they couldn't very well overturn all that precedent just to legalize drugs. (Imagine Scalia voting to make pot legal, then imagine him voting against states' rights. I'm sure he passed up sodomizing his wife to figure this one out.)
So the neo-federalists had to leave their constitution in exile a bit longer, and reaffirm what they may believe to be an excessively broad understanding of Congress's power, just to stiff some tokers.
You gotta love the law.
“Mary Jane's Last Dance” by Tom Petty & The Heartbreakers from the album Greatest Hits (4:33).