But it comes in the context of a lumbering cultural embrace of the drug. Legalization measures are anticipated on ballots in California and Oregon in 2020, and movements are afoot in Canada and Australia. In academia, clinical research on psychedelics is surging back into vogue, with at least some data now suggesting benefits for depression, anxiety, cluster headaches, obsessive-compulsive disorder, and pain, among other conditions.

Read: Prescribing mushrooms for anxiety

Such uses are recounted in Michael Pollan’s recent book, How to Change Your Mind, which details his own psychedelic escapades. Pollan depicts psychedelics as a promising medical treatment that was too long shunned by the medical community due to taboos and impediments to research funding. The case was convincing enough that the publisher included a disclaimer that the book is not “intended to encourage you to break the law.”

“The law” came after a post–World War II psychedelic boom. In 1947, the drug company Sandoz created lysergic acid diethylamide, or LSD, to treat psychosis. Then, as a shorter-acting alternative, the company made a synthetic version of psilocybin called Indocybin. It was sold until 1966, when the cultural tide turned again, in concert with a global crackdown on drugs that culminated in a 1971 meeting of the United Nations. The convention ruled that psychedelics such as MDMA, psilocybin, and LSD were to be prohibited “except for scientific and very limited medical purposes,” and that even those should be approved and closely monitored by the state.

In the United States, that meant research using these substances could be undertaken only after approval by the Drug Enforcement Administration. Mushrooms were classified as Schedule I drugs, along with heroin and other banned substances that were considered dangerous and without any medical use. This created regulatory hurdles for researchers, as well as called into question the very safety and legitimacy of doing research on a now-illegal drug in the first place. According to a history in the journal Nature Reviews Neuroscience, making psychedelic drugs Schedule I was “not based on any consideration of their physical harms, but on the assumption that there were no medical benefits.” And how could there ever be, if research was to be so limited?

This is finally being reconsidered, in what Pollan calls a “renaissance” of scientific thought. “If I lived in Denver, I think I would vote for [decriminalization],” Pollan told Anderson Cooper last week. “I just don’t think people should go to jail for the personal use of a psychedelic mushroom.”

Cooper furrowed his eyebrow and asked about concerns that mushroom decriminalization raises the “slippery slope” argument—that Denver’s move could lead to legalization and then, eventually, to some sort of nation of drugged-out, deadbeat dropouts. Pollan said he would not support legalization. But given the ongoing “mental-health crisis,” he said, the national mind should be open to psychedelic solutions.