Marijuana and William Randolph Hearst

The decision of the United States Congress to pass the Marijuana Tax Act of 1937 was based on hearings and reports. In 1936 the Federal Bureau of Narcotics (FBN) noticed an increase of reports of people smoking marijuana, which further increased in 1937.

The Bureau drafted a legislative plan for Congress, seeking a new law and the head of the FBN, Harry J. Anslinger, ran a campaign against marijuana. Newspaper mogul William Randolph Hearst's empire of newspapers began publishing what is known as "Yellow journalism", demonizing the cannabis plant and putting emphasis on connections between cannabis and violent crime. Several scholars argue that the goal was to destroy the hemp industry, largely as an effort of Hearst, Andrew Mellon and the Du Pont family.

They argue that with the invention of the decorticator hemp became a very cheap substitute for the paper pulp that was used in the newspaper industry.They also believe that Hearst felt that this was a threat to his extensive timber holdings. Mellon was Secretary of the Treasury and the wealthiest man in America and had invested heavily in nylon, DuPont's new synthetic fiber, and considered its success to depend on its replacement of the traditional resource, hemp. According to other researchers there were other things than hemp more important for DuPont in the mid-1930s: to finish the product (nylon) before its German competitors, to start plants for nylon with much larger capacity, etc. [source]