Cannabis Was Legal Federally From 1969 To 1970 Because Of This Court Case

This month marks the 49th anniversary of the decision in Leary v. United States, the often forgotten Supreme Court case from 1969 that effectively legalized marijuana on the federal level, when the Courts struck down the 1937 Marijuana Tax Act.

The Case

On December 22nd, 1965 Dr. Timothy Leary—a famous professor, psychologist, and political activist—was denied entry to Mexico, while on a road trip to Yucatan. Unable to proceed Leary turned around and stopped at an American inspection point to explain the situation where a boarder agent asked to search the vehicle. Upon inspection the boarder guard discovered small amounts of marijuana on the floor of the vehicle, and in the glove box. A personal search of Leary also produced a small silver snuff box with three partially burned joints.

Leary's possession of cannabis at a federally controlled international border put him in violation of the Marijuana Tax Act of 1937—the primary legislation used to enforce the prohibition on cannabis at the time. This event would lead to a federal trafficking conviction for him.

But Leary was prepared to fight. In 1968 he successfully brought his case to the Supreme Court arguing the Marijuana Tax Act violated the 5th Amendment.

The Marijuana Tax Act of 1937

The contradictions baked in to the Marijuana Tax Act became key to Leary’s defense. The Marijuana Tax Act stated that in order for someone to legally possess cannabis they were required to obtain a tax stamp. However, in order to receive a stamp you had to produce the cannabis. This effectively created an impenetrable loop. You needed a tax stamp in order to possess marijuana, but in order to get the tax stamp you had to possess marijuana that, by definition, did not have a stamp and was therefore an illicit substance. Obtaining legal cannabis was further complicated because all 50 states had their own laws deeming cannabis possession a criminal offense.

The Argument

Leary and his lawyers argued that the federal law violated the 5th Amendment of the Constitution—which bars mandatory self-incrimination. The argument was that in order for Dr. Leary to obtain the tax stamp required under federal law, he would have to produce marijuana to be taxed at the border. If Leary produced the marijuana however, he would be in violation of Texas state law which prohibited the possession of marijuana. Thus, the Marijuana Tax Act required him to violate state law and incriminate himself to government officials in order to be in compliance with federal law.

In a unanimous decision the Supreme Court held that the Marijuana Tax Act was in violation of Leary’s 5th Amendment right, and was thus unconstitutional. Their decision effectively ended federal marijuana prohibition.

Ramifications At The Time And For The Future

Dr. Leary’s astounding legal success was short lived however. The Supreme Court gave its final judgment on May 19th 1969, and on October 27th 1970 President Richard Nixon signed the Controlled Substances Act of 1970 which stands as the current federal law prohibiting the possession, sale, or use of marijuana.

While Leary’s success was short lived his case is notable for what it says about federal cannabis laws. Leary proved that with a well-argued case, and the right set of circumstances marijuana prohibition could be fought in the courts.

Unfortunately, the Supreme Court in recent decades has shown either an unwillingness or disdain for current attempts to end federal prohibition through the court. Specifically, with the disastrous decision of Gonzales v. Raich which allows federal agencies to raid cannabis operations even in states that have legalized the substance. The Supreme Court has missed an opportunity for clarity in federal marijuana policy with regards to state programs in Oklahoma and Nebraska v. Colorado.

On the anniversary of Leary v. United States, we should consider that many federal laws we live under may indeed be unconstitutional. With the proper argument, and a courageous Supreme Court, even cannabis laws can be changed.


Because it has been illegal or stigmatized for decades, the body of cannabis research available is, in many ways, incomplete. But Canada’s federal government is taking advantage of the country’s status as the only G7 country to have legalized marijuana and addressing that issue. It was announced yesterday that nearly 25 million dollars will be used to fund cannabis research in Canada.

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