But Lehman explains in detail why the second-order effects of marijuana legalization have mostly vindicated the pessimists and skeptics. First, on the criminal justice front, the expectation that legalizing pot would help reduce America’s prison population by clearing out nonviolent offenders was always overdrawn, since marijuana convictions made up a small share of the incarceration rate even at its height. But Lehman argues that there is also no good evidence so far that legalization reduces racially discriminatory patterns of policing and arrests. In his view, cops often use marijuana as a pretext to search someone they suspect of a more serious crime, and they simply substitute some other pretext when the law changes, leaving arrest rates basically unchanged.
So legalization isn’t necessarily striking a great blow against mass incarceration or for racial justice. Nor is it doing great things for public health. There was hope, and some early evidence, that legal pot might substitute for opioid use, but some of the more recent data cuts the other way: A new paper published in The Journal of Health Economics found that “legal medical marijuana, particularly when available through retail dispensaries, is associated with higher opioid mortality.” There are therapeutic benefits to cannabis that justify its availability for prescription, but the evidence of its risks keeps increasing: This month brought a new paper strengthening the link between heavy pot use and the onset of schizophrenia in young men.
And the broad downside risks of marijuana, beyond extreme dangers like schizophrenia, remain as evident as ever: a form of personal degradation, of lost attention and performance and motivation, that isn’t mortally dangerous in the way of heroin but that can damage or derail an awful lot of human lives. Most casual pot smokers won’t have this experience, but the legalization era has seen a sharp increase in the number of noncasual users. Occasional use has risen substantially since 2008, but daily or near-daily use is up much more, with around 16 million Americans, out of more than 50 million users, now suffering from what is termed marijuana use disorder.
In theory, there are technocratic responses to these unfortunate trends. In its ideal form, legalization would be accompanied by effective regulation and taxation, and as Lehman notes, on paper it should be possible to discourage addiction by raising taxes in the legal market, effectively nudging users toward more casual consumption.
In practice, it hasn’t worked that way. Because of all the years of prohibition, a mature and supple illegal marketplace already exists, ready to undercut whatever prices the legal market charges. So to make the legal marketplace successful and amenable to regulation, you would probably need much more enforcement against the illegal marketplace — which is difficult and expensive and, again, obviously uncool, in conflict with the good-vibrations spirit of the legalizers.