The status of marijuana legalization in the United States is a complex and evolving issue. Despite its illegal status at the federal level, over 50% of states, along with the District of Columbia, Guam, Puerto Rico, and the U.S. Virgin Islands, have legalized marijuana for medical use. This includes 21 states, DC, Guam, and the Northern Mariana Islands that have also enacted laws allowing the recreational use of marijuana.
However, states cannot fully legalize marijuana due to federal law constraints. Marijuana remains a Schedule I controlled substance under the Controlled Substances Act (CSA), making all activities involving marijuana federal crimes, regardless of state laws. The Supreme Court has reinforced this by holding that state laws authorizing medical marijuana use do not supersede federal law.
Historically, cannabis use was legal in the United States in the 1800s and used therapeutically. However, following the development of synthetic painkillers and increased media attention to cannabis-related violence, Congress outlawed recreational use in 1937, making access for medical use burdensome. Despite this, no state has reversed its legalization, medical or recreational, since California first legalized medical marijuana in 1996.
The Centers for Disease Control and Prevention (CDC) is actively working to understand and address the public health concerns of marijuana use. In 2019, marijuana was the most commonly used federally illegal drug in the United States, with an estimated 48.2 million people using it. Research suggests that approximately 3 in 10 people who use marijuana may develop marijuana use disorder, especially if they begin using it before age 18.
The incongruity between state and federal legislation regarding marijuana creates significant challenges. While many states have legalized cannabis for medical and/or recreational use, it remains illegal under US federal law, classified as a schedule I substance under the Federal Controlled Substance Act.