The Marihuana Tax Act of 1937

The Marihuana Tax Act of 1937 effectively criminalized marijuana at the federal level by imposing heavy taxes and strict regulations on its possession and sale. The law made it nearly impossible for doctors and pharmacists to prescribe cannabis legally. The act passed with minimal debate—many lawmakers didn’t understand what it was about. The American Medical Association opposed it, testifying that it was prepared in secret and would harm medical practice. This law marked the beginning of federal cannabis prohibition, bypassing constitutional limits through taxation authority.

In 1970, the Controlled Substances Act (CSA) classified marijuana as a Schedule I drug, alongside heroin and LSD, meaning it was deemed to have “no accepted medical use” and a “high potential for abuse.” This decision ignored recommendations from the Shafer Commission (1972), a bipartisan panel appointed by President Nixon, which concluded that marijuana should be decriminalized for personal use. Internal Nixon administration documents later revealed that the scheduling was politically motivated: to target anti-war activists and Black communities. As a former Nixon aide admitted, “We knew we couldn’t make it illegal to be against the war or Black, but by getting the public to associate hippies with marijuana and Blacks with heroin, we could disrupt those communities.”

Why was the use of marijuana really criminalized?