Why Is Marijuana Illegal? The History Of Cannabis In The U.S.

By Alex Halperin Jun 9, 2020

Cannabis has a long and complicated relationship with U.S. law. The plant was used and accepted as a medicine for many years before it was criminalized in the early 20th century. Hemp was also widely used throughout the 18th and 19th centuries for textile purposes. Both George Washington and Thomas Jefferson grew hemp

So  If, as a medicine and as a textile, cannabis proved to be a valuable resource, why did it become illegal?

One might think that keeping cannabis legal for its economic benefits would have been the right move.  However, many events happened to both criminalize the plant and convince people that it was a dangerous drug that would drive people insane, potentially even turn them into violent criminals in the process. 

In the process, a gross caricature of cannabis users was created to vilify the plant  Propaganda from the 1930s convinced many Americans that cannabis, which became known as marijuana at about the same time, was the devil.

Early History of Why Marijuana is illegal in America

In the early 17th century, King James I required that all property owners in the North American colonies grow 100 hemp plants. The crops would then be shipped back to England and used to make rope, ship sails, and clothing.

The use of hemp in America continued for hundreds of years as the U.S. gained independence and started to grow as a nation. However, once the Industrial Revolution kicked in, the hemp plant, which required intense labor to process started decreasing in popularity. Improvements in manufacturing facilities made it easier to manufacture cotton into textiles and for wood pulp to become the go-to material for paper production.

Hemp remained legal and in use for military purposes into the 20th century. But the plant was essentially not an important raw material by the time it was made illegal in 1939.

Why is Marijuana Illegal? A Brief Legal History of Cannabis in the United States

It wasn’t until the early 20th century that cannabis’ legal status came into question. In the early 1900’s cannabis use wasn’t mainstream or widespread. Cannabis was known in apothecaries as a medication and in the textile industry has a strong and durable fabric. Most people, however, weren’t generally aware of marijuana as a recreational drug.

That changed in the 1930s. Marijuana, or reefer as it was known back then, started gaining popularity as a recreational drug among artists and musicians, and  began spilling over into the mainstream.

The Federal Bureau of Narcotics was formed in 1930 and run by Harry J. Anslinger, who was determined to outlaw all recreational drugs. He believed consuming marijuana made people extremely violent, irrational, and overly sexual. Anslinger pushed to outright ban the plant and criminalize any recreational use. In 1936, he pushed for cannabis (among other plants) to be fully banned during the Convention for the Suppression of the Illicit Traffic in Dangerous Drugs. 

He wanted cannabis outlawed across the board, including for all medical and industrial purposes.. The focus of this convention was illicit trafficking, and in the end the U.S. refused to sign the treaty because they considered it too weak.

As time went on, the push to publicly demonize the cannabis plant continued unabated. Newspaper mogul William Randolph Hearst’s tabloids often attacked the drug. This type of misinformation spread rapidly, casting cannabis in a very negative light to the general public. Films like Reefer Madness portrayed marijuana smokers as psychopaths and deviants, influencing public opinion and making it possible for drastic prohibitive actions to be taken.

Why is Marijuana Illegal? Criminalization (1900s)

It wasn’t just yellow journalism that turned the public against the cannabis plant. There were numerous events, scare tactics, and types of fear-mongering used to sway public opinion against the  drug. Across the board, cannabis was  portrayed  as something that ruined users’ lives.

Why is Marijuana Illegal? The Mexican Connection

The Mexican Revolution of 1910 sent a large wave of Mexican immigrants into the United States. The consumption of marijuana in Mexico wasn’t very high and was outlawed in numerous Mexican states even before the Mexican government outlawed the plant in 1920. 

The U.S. government had been importing marijuana from India to be used for medical reasons, and many Mexicans were coming across the border to buy marijuana in pharmacies and smuggle it back into Mexico. That certainly didn’t help the narrative that was being pushed in the effort to demonize the plant and turn public opinion against it.

According to historian Isaac Campos, “cannabis came to gain this reputation in the 19th century, when it starts to appear as a recreational substance that’s smoked in cigarettes and is overwhelmingly concentrated in some of Mexico’s most marginal environments — prisons and soldiers’ barracks. So you have this drug that’s kind of associated with danger and indigenous Mexico, then in these environments associated with violence and danger. Then this mixes with a bunch of other stuff — [such as] widespread anti-alcohol sentiment especially among the elites — and that led people to think a drug like marijuana could trigger violent, savage responses in its users. Then all of this mixes with sensationalism in the press, which was always excited to write about violent incidents with the lower classes.”

It was very easy for the government to use this anti-immigrant angle to push for the criminalization of cannabis in the United States. Making it appear that cannabis was a “foreign” problem that was coming across the border and harming U.S. citizens was the perfect story to turn people against the plant.

Jazz and Assassins

Harry Anslinger also had it out for black jazz musicians in the early 20th century. Anslinger was overtly racist, so much so that he was even considered a “crazy racist” by his Pennsylvania senator who thought that Anslinger should have resigned because of his racist ways. 

Anslinger kept a file known as Marihuana and Musicians, targeting jazz artists like Billie Holiday and Charlie Parker, claiming their use of marijuana was influencing people to begin consuming the plant. He threatened Holiday to stop performing the song Strange Fruit and even handcuffed her while she was on her death bed at a New York hospital. She was there because of her heroin habit, a habit that started because Anslinger had one of his men track her down and frame her into buying and using heroin, leading to an 18-month stint in prison.

Anslinger and his men interfered in her methadone treatment at the New York hospital and she died within days, after having started to recover. All of this because Anslinger was hell-bent on silencing the musician who he believed was helping influence the use of marijuana.

This was only scratching the surface of the lengths Anslinger was willing to go to criminalize marijuana. In July of 1937, he wrote an article in The American Magazine called Marijuana: Assassin of Youth.

The article starts, “Not long ago the body of a young girl lay crushed on the sidewalk after a plunge from a Chicago apartment window. Everyone called it suicide, but actually it was murder. The killer was a narcotic known to America as marijuana, and to history as hashish. Used in the form of cigarettes, it is comparatively new to the United States and as dangerous as a coiled rattlesnake. How many murders, suicides, and maniacal deeds it causes each year, especially among the young, can only be conjectured.”

The article inspired the film, Assassin of Youth, another fear-mongering production similar to Reefer Madness that had a huge influence on the public opinion of marijuana; both films were based on extreme lies and gross exaggerations of the effects of cannabis.

The Marihuana Tax Act of 1937

All of these events led to the signing of the Marihuana Tax Act of 1937. The law, penned by Anslinger and signed by Franklin Roosevelt, was the first step in the long and sordid history of marijuana’s notorious legal reputation in the United States. 

While the act didn’t ban the use of marijuana outright, it legitimized fears that were stirred up by Anslinger and it played an important role in stigmatizing the plant, making it easier to pass other laws in the future on the road to criminalizing the plant.

The act made it so anyone who had anything to do with the cannabis plant – pharmacists, farmers, doctors, textile producers – had to pay additional taxes. This started to change people’s minds about cannabis, slowly turning people against the plant. The same year the act was passed, Moses Baca, a Mexican-American, was arrested by Anslinger’s Federal Bureau of Narcotics for the possession of a quarter-pound of marijuana that he didn’t pay taxes on, becoming the first of many people arrested for possession and the first real victim of the “war on drugs.”

Legality of Marijuana in the United States

A lot has changed in the days since Anslinger and his all-out war on cannabis. Sure, the legalization of cannabis across the board has yet to come in the U.S., but great strides have been made on the road to liberation. 

33 different states in the U.S. have legalized cannabis for medicinal purposes and 11 states (plus Washington D.C.) have legalized marijuana for recreational purposes. Each state has different laws regarding the legal status of cannabis for medicinal reasons.

This kind of progress could never have been imagined during the days of Anslinger and his assault on marijuana. The taboos surrounding marijuana have dissipated in the eyes of most Americans. In fact, two-thirds of Americans are in favor of legalizing marijuana for recreational purposes, putting an end to the federal prohibition of the plant. 


It’s safe to say that Harry Anslinger would be aghast if he were alive today to witness the progress that has been made with the decriminalization of marijuana. 

His life’s work was to make marijuana and those who used it, the enemies of the people, creating a narrative that was a brazen attack on reality, based on extreme conservatism and racism. 

Thankfully, those days are mostly behind us, though we still have a long way to go. The cannabis industry was built, and continues to sit atop extreme racial injustice. As many people open up cannabis companies and legally sell marijuana from designer dispensaries, many more people (mostly minorities) have criminal records or are in prison for doing the exact same thing, from out of their house. 

Not until marijuana is legalized recreationally on a federal level and all past offenders have their records expunged will we see true progress and reform for all.