Happy 4/20 to the millions of people across the country who celebrate, including much of the Reason staff. As someone who’s never been interested in pot—save for one summer in college—or drugs in general, I’ve always found the day a bit strange. But as I’ve grown older (and more libertarian), I’ve come to appreciate it as a celebration of personal freedom.
I’m not the only one who has changed his mind. In 2025, 64 percent of Americans thought marijuana should be legal for both medical and recreational use (up from 31 percent in 2000), according to Gallup. Meanwhile, 40 states have legalized medical use of cannabis, including 24 that also allow recreational use. Late last year, President Donald Trump ordered that marijuana be reclassified from Schedule I to Schedule III under the Controlled Substances Act, putting it in the same category as prescription drugs such as “ketamine, anabolic steroids, and Tylenol with codeine,” explains Reason‘s Jacob Sullum.
Prohibitionists warned that legalization would have dire consequences. Here are some of their predictions that have yet to come true.
In the lead-up to the 2012 vote on Amendment 64, which made Colorado the first state to legalize recreational marijuana, Douglas County Sheriff David Weaver warned that voters should anticipate “many harmful consequences” should the measure pass, including “more crime.”
According to a policy brief from Reason Foundation (which publishes this magazine), “the literature covering the relationship between marijuana use and violence appears to be largely inconclusive.” While research “generally suggests that marijuana use is associated with an increase in violent behavior,” the authors write, correlation is not causation, and several studies suggest otherwise.
After recreational marijuana was legalized in Colorado, Washington, and Oregon, homicide rates in those states remained well below the national average (although they rose during the COVID-19 pandemic, mirroring the national trend). From 1999 through 2022, the authors of the Reason Foundation report found, “both recreational and medical marijuana legalization” were “associated with a decrease in the homicide rate.” A 2013 report from the RAND Drug Policy Research Center likewise found “little support for a contemporaneous, causal relationship between [marijuana] use and either violent or property crime.”
Yet prohibitionists stand by their forecast. In March, Ohio Speaker of the House Matt Huffman (R–Lima) defended proposed limits to THC content in the state by saying that legalization in Ohio has led to “more marijuana being available in the community,” causing “more crime.”
Sheriff Weaver also warned that legalization would result in “more kids using marijuana.” That fear was also overblown.
In 2022, Nora Volkow, director of the National Institute on Drug Abuse, noted that “in the United States, legalization by some states of marijuana has not been associated with an increase in adolescents’ marijuana use.” Nationwide, reported drug use among teenagers has been declining for several years. In 2024, the National Institutes of Health found that “substance use among adolescents has continued to hold steady at lowered levels for the fourth year in a row.” Volkow called these results “unprecedented” and implored the scientific community to continue investigating “factors that have contributed to this lowered risk of substance use.”
One reason could be legalization. Pulling together the results of government surveys, the Marijuana Policy Project has found that past-month pot use by teenagers has fallen in most states where recreational use is legal. In Michigan, for instance, 17 percent of high school students reported past-month marijuana use in 2023, down from 24 percent in 2017. In Virginia, the rate fell from 17 percent in 2019 to 9.5 percent in 2023.
While there could be several reasons why teens are smoking less pot—including increased use of other drugs—one thing seems certain: Weed legalization did not produce a generation of stoners.
There were also widespread predictons that legalization would increase traffic accidents. The data are decidedly mixed and inconclusive on this one.
In 2021, the Insurance Institute for Highway Safety (IIHS) released a study that found traffic accidents rose by 7 percent in legalized states after legalization. The same study also concluded that traffic fatality rates did not rise by a statistically significant amount and “state-licensed recreational sales had no apparent impact on injury rates,” Reason‘s Jacob Sullum reported at the time. That same year, the IIHS found that drivers who used only cannabis were no more likely to get into car accidents than drivers who hadn’t used the drug.
Mixed results like these are not uncommon. As Reason Foundation researchers concluded in a white paper: “There are few convincing conclusions to be drawn concerning the risk of traffic accident fatalities from marijuana legalization….All in all, no conclusive or definitive patterns related to cannabis legalization have appeared in the data or research to this point.”
