(Medical Cannabis and the Constitution's Commerce Clause) "Congress has exercised its Commerce Clause authority to categorically ban marijuana. The Supreme Court has upheld this plenary prohibition.19 In Gonzales v Raich, a divided Court held that the Commerce Clause enables Congress to prohibit the local cultivation and use of marijuana, despite more permissive regulations under California law.20 Writing for the majority, Justice Stevens found that precedent 'firmly established' Congress’ power under the Commerce Clause to regulate purely local activities that have a substantial effect on interstate commerce.21 The Raich majority held that Congress can prohibit local marijuana cultivation and use, because it was part of a 'class of activities' constituting the national black market for marijuana.22 The Court reasoned that local cultivation and use, even for limited medical purposes, affected supply and demand in the national black market, making regulation over local use 'essential' to undermining the broader underground industry nationwide.23 The majority distinguished Raich from earlier precedent that circumscribed Congress’ Commerce Clause power, finding that those earlier cases involved statutes that regulated purely non-economic activities, while this one aims to nullify a particular application of a valid statutory scheme.24"

Source

Woods, Jordan Blair, "The Kingpin Act vs. Calfornia's Compassionate Use Act: The Dubious Battle Between State and Federal Drug Laws," University of the District of Columbia Law Review (Washington, DC: The University of the District of Columbia David A. Clarke School of Law, 2011) Volume 15, Number 1, p. 50.
http://www.udclawreview.com/w…