Marijuana has lit up conversations and controversy across the country. It’s a hotly contested and complicated issue for states to weed through, and no doubt will remain high on legislative agendas for the foreseeable future. There are important themes when “diving deep” into the topic of marijuana and lessons to be learned from the states that have taken the dive.

Voters in Alaska, Arizona, California, Colorado, Maine, Massachusetts, Michigan, Montana, Nevada, New Jersey, Oregon, South Dakota, Washington and the District of Columbia have legalized small amounts of marijuana for adult use. Colorado and Washington’s measures passed in 2012. Initiatives in Alaska, Oregon and the District of Columbia passed in the fall of 2014, while initiatives in California, Maine, Massachusetts and Nevada passed in 2016. As of Jan. 22, 2018, the Vermont legislature passed adult-use legalization legislation but did not pass regulations until October 7, 2020. The legislative bodies in Illinois and Guam passed adult-use legalization measures in 2019, bringing the total number of adult-use states to 15 and territories to three as of November 5, 2020.

Federal Considerations—Marijuana is a Schedule I drug under federal law. It is defined as dangerous, has no currently accepted medical use and has a high potential for abuse. This complicates taxation, banking and other areas regulated by federal laws.

Decriminalization—Twenty-seven states and the District of Columbia have decriminalized the possession of small amounts of marijuana for personal consumption. Generally, in these states, possession is treated as a civil or local infraction (or a minor misdemeanor with no jail time), instead of a crime.

Medical Marijuana—With 36 states, the District of Columbia, Guam, Puerto Rico and U.S. Virgin Islands having comprehensive medical marijuana programs and at least another 11 states allowing the use of products with low-THC (the active ingredient in marijuana) for medical purposes, most states have some experience with the legalization of medical marijuana.

Regulations and Taxation—Alaska, Colorado, Oregon and Washington are developing their own unique structures to collect tax revenue, and license and regulate marijuana cultivation facilities and retail shops. The newly approved programs will take some time to finalize their regulations and tax structures.

Impairment While Driving—New cannabis products, unfamiliar new strains, and the fact that people metabolize and retain THC differently than they do alcohol, make it difficult to determine levels of impairment. Currently, Colorado and Washington use a threshold of 5 nanograms or more of THC per milliliter of blood as a measurement for driving under the influence of cannabis.

Public Safety—States are trying to balance regulating a legal marijuana market for adults while preventing access by children. This includes requiring identification checks at dispensaries, prohibiting anyone under age 21 inside dispensaries, requiring child-resistant packaging of cannabis products and prohibiting the use of marijuana in public. 

Education and Prevention— States are also supporting research and educating the public about the personal health effects of marijuana, offering prevention programs for adolescents, and working hard to debunk any possible misperception that marijuana is acceptable, legal and safe for children, whose brains are still developing.



State Legislatures Magazine


Marijuana and Federalism

Learn about the legal issues associated with intergovernmental marijuana authority and enforcement, and hear about interstate litigation and states' rights in this NCSL Legislative Summit session.



marijuana timeline

State Marijuana Policies Timeline- *Pending 2019-2020 update*

This timeline shows the progression of marijuana legislation in the states since California first legalized medical marijuana in 1996.


By the Numbers


States that have legalized medical marijuana along with D.C., Guam, Puerto Rico and US Virgin Islands.


States with regulated adult-use marijuana programs, along with three territories.

Nearly $250 million

2017 Colorado taxes, licenses and fees.


Voters in five states passed eight marijuana-related ballot initiatives in 2020