The historical roots of cannabis vary widely and run parallel to the development of the Silk Road. Accordingly, the plant was first used by the Chinese empires, followed by the Persian empire, and then introduced to western Europe around the 16th century, appearing as an herbal medicine in botany texts.
Following the trade routes, the cultivation of hemp in North America was not only legal, but mandatory under King James I. Likewise, several American founders, including George Washington, referenced growing hemp alongside tobacco in the 18th century.
The use of cannabis for THC purposes in US was first reported widely in the 19th century. THC was introduced to European soldiers en masse during the age of imperialism and subsequently imported to Europe. It became popular amongst the European bourgeoisie and spread quickly to their counterparts in the US. Likewise, smoking marijuana was popular amongst Mexican immigrants in the 19th Century, who introduced the practice to their southwestern neighbors without sanction.
By the turn of the 20th century, cannabis could be found in most pharmacies as an over-the-counter remedy for a variety of physical ailments. However, moralists blamed adulterated substances for uncharacteristically violent behavior, and the newly minted Food and Drug Administration labeled marijuana a poison.
In the 1920s, cannabis was a target of the Prohibition movement. By the 1930s, a majority of states adopted bans against marijuana. The Uniform Narcotics Act was proposed to states from the Federal Bureau of Narcotics. Notably, the 1936 film "Tell Your Children," was widely distributed with the intent of warning children of the dangers of cannabis. Subsequently, the Marihuana Tax Act of 1937 placed a relatively small federal tax on the sale of small amounts of marijuana, but it did not criminalize it on the federal level. Subsequently, "Tell Your Children" became popular much later as an unintentional comedy known as "Reefer Madness," which is still available today.
State regulations varied with the turn of the 20th century. The Boggs Act of 1952 and the Narcotics Control Act of 1956 established and increased federal mandatory minimum sentencing for possession of the substance.The Controlled Substances Act of 1970 labeled cannabis a Schedule I drug as part of the War on Drugs, revoking the previous minimum sentences and re-enforcing beliefs that marijuana was a dangerous substance.
Recent court decisions have generally upheld the use of marijuana as a crime. However, the Alaska Supreme Court ruled in 1975 that private use of a small amount of marijuana in one's home was protected under a constitutional right to privacy, effectively lifting the state ban on some uses of the substance. Alternatively, the Supreme Court of the United States addressed the issue in two recent cases from California, where it established that private distribution of medical marijuana continues to be a federal crime, regardless of the state's referendum to allow it.