Nearly four decades ago, Francis Young, chief administrative law judge at the Drug Enforcement Administration (DEA), concluded that marijuana did not belong in Schedule I of the Controlled Substances Act, the law's most restrictive category. Although Young was ultimately overruled by DEA Administrator John Lawn, he was belatedly vindicated last week, when President Donald Trump ordered the "expeditious" reclassification of marijuana.

Under Trump's executive order, marijuana will be moved from Schedule I, which includes banned substances such as heroin, LSD, and MDMA, to Schedule III, which includes prescription drugs such as ketamine, anabolic steroids, and Tylenol with codeine. While that move falls far short of legalization, it implicitly acknowledges that the federal government has been exaggerating marijuana's hazards and ignoring its potential benefits for more than half a century.

Marijuana has been listed in Schedule I, which supposedly is reserved for especially dangerous drugs with a high abuse potential and no accepted medical applications, since 1970. The DEA has repeatedly rejected petitions asking it to reconsider that classification, including the one that resulted in Young's 1988 decision, which followed 16 years of litigation.

Because marijuana is "one of the safest therapeutically active substances known to man," Young said, "there is accepted safety for use of marijuana under medical supervision." He also concluded that marijuana had "currently accepted medical use" as a treatment for conditions such as nausea caused by cancer chemotherapy and spasticity caused by multiple sclerosis.

The federal government nevertheless continued to defend marijuana's Schedule I status until 2023, when the Department of Health and Human Services (HHS) completed a review ordered by President Joe Biden. HHS found "credible scientific support" for marijuana's utility as a treatment for pain, nausea and vomiting, and "anorexia related to a medical condition."

HHS said that evidence, combined with the practices of clinicians in states that recognize marijuana as a medicine, was enough to establish "currently accepted medical use." The review also assessed the drug's hazards, noting that "the vast majority of individuals who use marijuana are doing so in a manner that does not lead to dangerous outcomes to themselves or others."