In the U.S., continued growing alarm over drug addiction, the rising Temperance Movement for alcohol, and a desire to maintain credibility with its international partners upon pushing for the 1912 Opium Convention, motivated the U.S. to pass its first major national antinarcotic law, the Harrison Act of 1914.
Championed by Congressman Francis Barton Harrison, it would control the production, sale and use of opium (and its derivatives), cocaine, and cannabis. Marijuana was left out of the final bill, however, due to resistance by many in the medical field who believed that it was not habit-forming. Marijuana thus remained effectively legal in the U.S. until 1937 when Congress passed the Marihuana Tax Act. Instead of directly prohibiting marijuana, the Tax Act imposed a transfer tax stamp of $100 per ounce each time the drug changed hands. Unsurprisingly, the stamps were seldom issued, effectively rendering the drug illegal.
Formalized drug control, the lingering effects of the economic depression and World War II all contributed to a major decline in drug use and abuse in the U.S. in the ensuing decades. Essentially, illegal drugs became a relatively uncommon and forgotten problem. Yet, as history often demonstrates, the lull in drug use was not indefinite.