In 1970, President Nixon signed the Controlled Substances Act and placed cannabis in Schedule I, the most restrictive category, alongside heroin. His own commission recommended against it. He ignored them. The aide who helped design the strategy later admitted on record that the war on drugs was designed to target Black people and antiwar protesters, not to address genuine public health concerns. That context, the political rather than scientific origins of federal cannabis prohibition, is where the modern legalization story has to start.
What followed was a fifty-year journey from one of the most aggressively enforced drug prohibitions in American history to a point where more than half of American states have legalized recreational cannabis and seventy percent of Americans support full legalization. Here is how it actually happened.
Quick Answer: When Was Cannabis Legalized in the United States?
Cannabis is not federally legal in the United States as of August 2026. However, 24 states and Washington DC have legalized recreational adult-use cannabis and 38 states have some form of legal medical cannabis. Colorado and Washington were the first states to legalize recreational cannabis in 2012. California was the first state to legalize medical cannabis in 1996. The legal landscape has transformed dramatically since the early 1990s and continues to evolve.
Before Prohibition: Cannabis in Early America
Cannabis was a common agricultural product in colonial and early America. Hemp was cultivated for rope, textiles, and paper. Cannabis as a medicine appeared in the United States Pharmacopeia from 1850 to 1942. Tinctures of cannabis were sold in pharmacies without prescription. There was no federal prohibition and no particular cultural anxiety about the plant through most of the nineteenth century.
The shift began in the early twentieth century, intertwined with immigration anxieties. Mexican immigrants who crossed into Texas and the Southwest brought cannabis for recreational use, called marijuana or marihuana. The association of cannabis with Mexican immigrants, and later with jazz musicians and Black communities in New Orleans and other cities, drove early prohibition efforts that were explicitly racialized in their framing.
The Marihuana Tax Act of 1937
Harry Anslinger, the first commissioner of the Federal Bureau of Narcotics, led a campaign through the 1930s that associated cannabis with crime, violence, and racial minorities. His testimony before Congress in 1937 was built largely on anecdote and misinformation. The American Medical Association testified against the proposed legislation. Congress passed the Marihuana Tax Act anyway, effectively prohibiting cannabis at the federal level through a prohibitive tax structure rather than outright criminalization.
The Act was the culmination of state-level prohibition efforts that had spread through the 1920s and 1930s, often explicitly linked to anti-immigrant and anti-Black sentiment in legislative debates. The historical record on this is not ambiguous.
The Controlled Substances Act of 1970
The Marihuana Tax Act was struck down by the Supreme Court in 1969 in a case brought by Timothy Leary. Congress responded immediately with the Controlled Substances Act, which placed cannabis in Schedule I alongside heroin as having no accepted medical use and high potential for abuse. President Nixon appointed the Shafer Commission to evaluate the scheduling. The commission recommended decriminalization. Nixon rejected the recommendation and launched the War on Drugs.
The Controlled Substances Act created the federal enforcement framework that has governed cannabis policy for more than fifty years. The Schedule I classification is the legal obstacle to federal legalization and research, and changing it requires either congressional action or DEA rulemaking.
The 1970s and 1980s: Decriminalization and the War on Drugs
Despite Nixon’s escalation, eleven states decriminalized small amounts of cannabis for personal use during the 1970s. Oregon was first in 1973. These states removed criminal penalties for possession of small amounts, replacing them with civil fines. Public opinion polls showed majority support for decriminalization in some of these states. The trajectory looked like it was heading toward broader reform.
Then the 1980s arrived. The Reagan administration doubled down on drug enforcement, increased mandatory minimum sentences for drug offenses, and launched the Just Say No campaign. Cannabis arrests climbed dramatically through the 1980s and 1990s, disproportionately affecting communities of color despite comparable use rates across racial groups. By the late 1990s, the United States was incarcerating more of its population for drug offenses than any country on earth.
1996: California Changes Everything
California’s Proposition 215, the Compassionate Use Act, passed in November 1996 with 55.6 percent of the vote. It allowed seriously ill Californians to obtain and use cannabis for medical purposes recommended by a physician. It was the first successful state-level medical cannabis legalization in the country and it opened a door that has never closed.
The Clinton administration threatened to prosecute doctors who recommended cannabis. The courts ruled against the federal government. California’s medical dispensary industry grew slowly through the late 1990s and expanded significantly in the 2000s. By 2010 Los Angeles had more medical cannabis dispensaries than Starbucks locations.
The Medical Cannabis Expansion: 1998 to 2012
Oregon, Washington, Alaska, Maine, Hawaii, Nevada, Colorado, Montana, Vermont, Rhode Island, New Mexico, Michigan, New Jersey, Arizona, Delaware, Connecticut, Massachusetts, and Washington DC all passed medical cannabis legislation between 1998 and 2012. Each state’s program had different qualifying conditions, possession limits, and licensing structures. This patchwork of state programs created an industry infrastructure and a political coalition that would power the push for full legalization.
2012: The First Recreational Legalizations
Colorado’s Amendment 64 and Washington’s Initiative 502 both passed on November 6, 2012, making Colorado and Washington the first jurisdictions in the world to legalize recreational cannabis for adults. The margin in Colorado was 55.3 percent. In Washington it was 55.7 percent. The Obama administration announced it would not challenge the state laws, a critical decision that allowed implementation to proceed.
Colorado’s recreational stores opened January 1, 2014. The lines were long. The tax revenue was immediate and substantial. Colorado’s experiment became the reference point for every subsequent state legalization debate.
2016: California, Nevada, Massachusetts, Maine, and More
The 2016 election cycle produced the largest single-year expansion of cannabis legalization in history. California’s Proposition 64 passed with 57 percent of the vote, bringing the world’s fifth-largest economy into the legal cannabis market. Nevada, Massachusetts, and Maine also passed recreational measures. Medical cannabis expanded to Florida, North Dakota, Arkansas, and Montana. The scale of the 2016 wave shifted the political calculus in states that had been waiting to see how early legal states performed.
2020 and Beyond: Legalization Goes Mainstream
Five more states legalized recreational cannabis in the 2020 election cycle: New Jersey, Arizona, South Dakota, Montana, and Mississippi for medical. South Dakota’s recreational measure was later struck down in court on procedural grounds. New York passed legalization through the legislature in 2021. Virginia, New Mexico, Connecticut, Rhode Island, Maryland, Missouri, and several others followed in 2021 to 2023.
By 2026, recreational cannabis is legal in 24 states and Washington DC. The political movement that began with one California ballot measure in 1996 has reached a point where federal legalization is debated in Congress rather than treated as a fringe position.
Federal Reform Efforts
The MORE Act, the SAFE Banking Act, and various federal legalization proposals have moved through different stages of the legislative process without becoming law. The DEA proposed moving cannabis from Schedule I to Schedule III in 2024, which would acknowledge its medical value but stop short of full legalization. Congressional action has been hampered by divided government and the challenge of building a coalition across both chambers and both parties. The trajectory points toward eventual federal reform but the timeline remains genuinely uncertain.
Frequently Asked Questions
When was cannabis made illegal in the United States?
The Marihuana Tax Act of 1937 effectively prohibited cannabis federally. The Controlled Substances Act of 1970 placed it in Schedule I, the current legal framework.
Which state was first to legalize medical cannabis?
California in 1996 with Proposition 215, the Compassionate Use Act.
Which states were first to legalize recreational cannabis?
Colorado and Washington in 2012. Retail sales opened in Colorado on January 1, 2014.
Is cannabis federally legal in the United States?
No. Cannabis remains Schedule I under the Controlled Substances Act as of August 2026. The DEA proposed rescheduling to Schedule III in 2024 but this has not been finalized.
Author: Paul Jernigan covers cannabis law and policy for Ganjly.
Related: Read Ganjly’s guide to current federal cannabis law and our complete state legal guide.
