Cannabis is the most commonly used illegal drug in the world. Despite its current legal status it only became criminalised within the last century, before which it was both a regularly used recreational drug as well as a medically prescribed drug for dealing with a wide range of ailments from glaucoma to cancer and multiple sclerosis. So if merely a century ago Marijuana was a widely used and medically acknowledged drug how did it manage to reach the criminalised status that it now holds?

In America the criminalisation of cannabis began as a relatively slow and understated process with certain states outlawing its use starting in the District of Columbia in 1906. A couple of states followed this example and outlawed the use of cannabis throughout the 1910s and 20s but it wasn't until the 1930's that the criminalization of cannabis became a major issue.

The reason that cannabis became such a huge issue was the launch of a massive smear campaign against marijuana lead by Harry J Anslinger from 1930 to 1937. Harry J Anslinger started his career as the Assistant Prohibition Commissioner in the Bureau of Prohibition before he was promoted to the position of Commissioner in the newly created Federal Bureau of Narcotics in 1930. Anslinger held this position for 32 years, but it is his campaign against marijuana, which dominated the first 7 years of his tenure, that he is most widely remembered for.

Anslinger made heavy use of the mass media in order to spread his anti-cannabis message. Anslinger notoriously fabricated a number of stories tenuously linked to police reports that he published in his "Gore File" and used to turn the public against the drug and gain backing for its criminalisation. Among the accusations he levied were "There are 100,000 total marijuana smokers in the US, and most are Negroes, Hispanics, Filipinos and entertainers. Their Satanic music, jazz and swing, result from marijuana usage. This marijuana causes white women to seek sexual relations with Negroes, entertainers and any others."; "Reefer makes darkies think they're as good as white men."; "You smoke a joint and you're likely to kill your brother." These accusations were designed to pray on the worries that many American's had about the number of immigrants entering the country.

A more interesting point relating to this is that Anslinger wanted the growth of all marijuana plants outlawed; including those that yield no intoxicating chemicals and can only be used to produce the extremely versatile textile hemp and cannabis oil which can form a cheap and effective base for fuels, paints and plastics. Anslinger and his primary supporter, William Randolph Hearst, both had considerable interest in the petrochemical industry and it has been suggested that the anti-cannabis campaign was primarily designed to eliminate hemp as a competitor.

No matter the reasons it is clear that Harry J Anslinger and his anti-cannabis activism played an enormous role in the national criminalisation of the drug, something which is still strongly debated to this day.