Cannabis laws in the United States have evolved dramatically over the past century. What began as a widely cultivated agricultural crop eventually became one of the most heavily regulated plants in the country. Today, cannabis exists in a complex legal landscape where federal and state laws sometimes differ.
Understanding the history of cannabis legislation helps explain why hemp, CBD, and marijuana are regulated differently today.
Early Cannabis Restrictions in the United States
In the early 1900s, cannabis was not heavily regulated and was used in a variety of industrial and medicinal applications. However, attitudes toward intoxicating substances began to shift during the Prohibition era, when many states started introducing stricter drug laws.
By 1931, cannabis had been outlawed in 29 states. Public concern about intoxicating substances and changing political attitudes toward drugs contributed to the increasing restrictions placed on cannabis.
The Marijuana Tax Act of 1937
One of the most significant early federal regulations was the Marijuana Tax Act of 1937.
Rather than banning cannabis outright, the law imposed heavy taxes and strict regulatory requirements on the sale, possession, and transfer of cannabis products, including hemp. These restrictions made it extremely difficult to legally produce or distribute cannabis in the United States.
Although the act technically allowed industrial hemp production, the regulatory burden effectively criminalized most uses of the plant.
Hemp Production During World War II
During World War II, the U.S. government briefly encouraged hemp cultivation again due to the plant’s importance in producing rope, canvas, and other wartime materials. Farmers were encouraged to grow hemp as part of the “Hemp for Victory” campaign.
After the war ended, hemp cultivation once again declined. The final legal hemp fields in the United States were planted in Wisconsin in 1957.
The Controlled Substances Act of 1970
A major turning point in cannabis regulation came in 1970, when President Richard Nixon signed the Controlled Substances Act (CSA).
This legislation repealed the Marijuana Tax Act and officially classified marijuana as a Schedule I controlled substance. Drugs in this category were considered to have a high potential for abuse and no accepted medical use.
Cannabis was placed in the same category as substances such as:
- heroin
- LSD
- ecstasy
This classification made cannabis illegal at the federal level and severely limited research and legal access to the plant for decades.
The Rise of Medical Cannabis Laws
Cannabis laws began to shift in the 1990s, when public attitudes toward medical marijuana started to change.
In 1996, California passed the Compassionate Use Act, becoming the first state to legalize cannabis for medical purposes. This allowed patients with certain medical conditions to legally access cannabis with a doctor’s recommendation.
Over the following years, many other states introduced similar medical cannabis programs.
Recreational Cannabis Legalization
The next major milestone came in 2012, when Colorado and Washington became the first states to legalize cannabis for recreational use.
Since then, numerous states have passed laws allowing adults to legally purchase and possess cannabis. However, the specific regulations vary widely from state to state.
Some states allow full recreational sales, while others only permit medical cannabis programs.
The Legal Status of Hemp
Although marijuana remains illegal at the federal level, hemp is treated differently under U.S. law.
The 2018 Farm Bill legalized hemp at the federal level by defining it as cannabis containing 0.3% THC or less by dry weight. This change allowed farmers to legally grow hemp and made it possible for companies to produce hemp-derived products such as:
- CBD oil
- hemp extracts
- hemp seed foods
- hemp fiber products
Because hemp contains very low levels of THC, it does not produce intoxicating effects.
Federal vs. State Cannabis Laws
Today, cannabis exists in a complicated legal environment. While many states have legalized medical or recreational cannabis, marijuana is still classified as a Schedule I substance under federal law.
This means the legality of cannabis products often depends on where you live and the type of product involved.
Hemp-derived products that comply with federal THC limits are widely available across the United States, while marijuana laws vary significantly from state to state.
The Bottom Line
Cannabis laws in the United States have undergone major changes over the past century. The plant was heavily restricted for decades under federal law, but attitudes have shifted in recent years as more states legalize cannabis for medical or recreational use.
Hemp was federally legalized in 2018 and is now widely used to produce CBD products and other hemp-derived goods. However, marijuana laws still vary across the country, creating a complex legal landscape for cannabis-related products.