Two cases, two different constitutional questions
Cannabis litigation has challenged both the tools used to enforce prohibition and the power of governments to regulate the plant. Two US Supreme Court decisions illustrate the difference. Leary v. United States, decided on 19 May 1969, concerned self-incrimination and proof in a criminal prosecution. Gonzales v. Raich, decided on 6 June 2005, concerned federal authority over cannabis used medically under California law. Their outcomes moved in different directions.
1969: the tax return that could incriminate its filer
The Marihuana Tax Act used registration, order forms and transfer taxes to control cannabis. Timothy Leary argued that complying with its transfer-tax requirements would identify him to authorities in circumstances exposing him to prosecution.
The Court held that the Fifth Amendment privilege against self-incrimination provided a complete defence to the specific tax charge. It also rejected, in the circumstances of the case, a statutory presumption that possession established knowledge of unlawful importation. The decision attacked particular enforcement mechanisms; it did not create a general constitutional right to cannabis.
1970: Congress replaced the older system
Congress subsequently adopted the Controlled Substances Act as part of the 1970 federal drug legislation. It replaced earlier revenue-based controls with a comprehensive system of schedules, registration and restrictions. A successful challenge to one statute had therefore not ended federal regulation. The legal basis of the system changed.
2005: California permission and federal power
Angel Raich and Diane Monson relied on California’s medical-cannabis legislation. They challenged application of the federal Controlled Substances Act to local, noncommercial medical use. Their argument was that this activity fell outside Congress’s power over interstate commerce.
The Supreme Court upheld federal authority. The majority treated locally produced and consumed cannabis as part of the broader market Congress could regulate, rather than an isolated category beyond federal reach. State-level permission consequently did not prevent enforcement of the federal statute in this case. The judgment addressed constitutional power, not a clinical assessment of the patients’ treatment.
2018: Canada changed the legislation itself
Canada’s Cannabis Act took effect on 17 October 2018. Parliament created a national regulatory framework, with responsibilities shared between federal, provincial and territorial governments. Unlike a judgment removing a particular unconstitutional provision, this was legislation establishing a new system.
Together, these milestones show three distinct forms of change: invalidating an enforcement mechanism, confirming a government’s regulatory authority, and legislating a replacement framework. That distinction explains why a major court victory does not necessarily amount to legalisation.
Sources & further reading
General information, not individual legal or medical advice.