Not a Constitutional scholar, but familiar with this Court -- the only possible surprise is that federal drug policy trumped States' rights for Scalia, so he and Thomas voted on opposite sides (very rare).  We can fairly assume that the States' Rightists who voted in the minority -- Rehnquist, O'Connor (who wrote for the minority), Thomas -- would support a State prohibition on marijuana (as would the other six).  -- Jared Lobdell