Congress may ban the use of marijuana even in states that have approved its use for medicinal purposes. Decided June 6, 2005 (argued November 29, 2004). Opinion of the Court: John Paul Stevens → go there Dissenting: O'Connor, Thomas. Topic: Federalism. Gonzales v. Raich, 545 U.S. 1 (2005), was a decision by the U.S. Supreme Court ruling that, under the Commerce Clause of the U.S. Constitution, Congress may criminalize the production and use of homegrown cannabis even if state law allows its use for medicinal purposes. Wiki link