U.S. marijuana laws: A history

For decades, state and federal lawmakers and U.S. residents have navigated the ever-evolving policies that determine who can legally use marijuana and in what form it may legally be consumed. Early this year, Attorney General Jeff Sessions complicated that navigation by giving federal prosecutors permission to try pot cases in states that have legalized it, a reversal of Obama-era policy.

The history of U.S. marijuana legislation is long and complex. Here, we offer a shortened version in five maps that show which states have legalized what — and when. But first, the lingo...

CBD (cannabidiol): A non-psychoactive substance in marijuana that provides medical benefits.

medical marijuana: Doctor-recommended to ease symptoms of certain conditions; contains both delta-9-tetrahydrocannabinol, or THC (psychoactive) and CBD.

recreational pot: Used without medical justification; often contains more THC than medical marijuana.

decriminalization: When states lessen the penalties for possessing small amounts of pot but keep trafficking and possession of large amounts criminally illegal.

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On the heels of President Ronald Reagan’s “war on drugs,” during which new federal mandatory minimum sentences were introduced, states began legalizing the use of medical marijuana.

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As pot became more mainstream and viewed as less harmful than than it was seen as being during the Reagan administration, the states that paved the way for medical marijuana began allowing it for recreational purposes as well.

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Incarceration rates spiked under the Reagan-era policies, disproportionately affecting men of color.

By the 2000s, states began to reconsider the war on drugs. Some chose to combat it by decriminalizing, rather than legalizing, marijuana. Decriminalization laws vary from state to state and may favor fines over jail, or short jail time over prison. In addition, the definitions for what they consider a small amount of pot could differ.

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A third category of legalization involves a type of medical cannabis that is low in THC, the psychoactive component in pot, and high in CBD, the non-psychoactive component. It is to be used only by patients with intractable seizure disorders, according to the Marijuana Policy Project.

These laws are more restrictive than comprehensive medical marijuana laws and can exclude patients with cancer or AIDS. Some limit the use of CBD oil to clinical trials. Others legalize the use of CBD oil without providing avenues to obtain it legally.

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But openness to CBD from a medical and legal perspective is ever-evolving. Just this week, Food and Drug Administration advisers offered unanimous support for what may become the first government-approved medication made from CBD.

Even Sen. Orrin G. Hatch (R-Utah) joined the conversation Thursday — just before the unofficial weed-smoking holiday 4/20 — when he tweeted about a bipartisan effort calling on Sessions to stop blocking medical marijuana research: “We’ll get in the weeds to hash out some of the most potent arguments as to why it might be the budding answer doctors have long strained to find for countless chronic conditions.”