For the past three years, we have co-taught a seminar in Neuroscience and Criminal Justice at Tufts University’s Experimental College. If the recent joint opinion piece by Governor Charlie Baker, Attorney General Maura Healey, and Mayor Marty Walsh had been submitted as a paper in our class, it would receive an “F” for critical reasoning skills.

First, Baker, Healey, and Walsh’s jeremiad against marijuana legalization relies heavily on junk science and faulty statistical reasoning. For example, they place extraordinary emphasis on a “report from the Rocky Mountain High Intensity Drug Trafficking Area,” (RMHIDTA) which catalogs seemingly alarming increases in various “marijuana-related” incidents in Colorado (ER visits, traffic deaths, etc.) following legalization.

Baker, Healey and Walsh fail to mention, however, that the RMHIDTA report cautions — in all-caps — that “TERMS SUCH AS ‘MARIJUANA-RELATED’ OR ‘TESTED POSITIVE FOR MARIJUANA.’ … DO[] NOT NECESSARILY IMPLY THAT MARIJUANA WAS THE CAUSE OF THE INCIDENT.” In other words, all that these numbers reflect is that since legalization in Colorado, more people are using marijuana — not that marijuana is causing more accidents or more ER visits.

Baker, Healey, and Walsh are also playing games when they suggest that legalization in Colorado caused an increase in marijuana exposure among children. In fact, the numbers are far too small to show a statistically significant trend. According to the RMHIDTA, in the year following legalization, Colorado averaged fewer than forty total incidents of marijuana-related exposure for young children — in a state with a population of 5.35 million.

Perhaps the most ridiculous claim offered by these prohibitionist politicians is their assertion that “[e]ven an untrained eye can see differences between the MRI brain images of those who habitually use marijuana and those who don’t.”

False. The Journal of Neuroscience — the official, peer-reviewed journal of the world’s largest organization of neuroscientists — recently published an analysis, based on MRI scans, which found that daily marijuana use did not have “even a modest effect” on volumetric or shape differences in subcortical structures. It criticized earlier studies — on which Baker, Healey, and Walsh apparently relied — for failing to account for a critical confounding variable: “alcohol abuse [which] has been unequivocally associated with deleterious effects on brain morphology and cognition in both adults and adolescents.”

Which leads to the second — and most critical — flaw in this bipartisan entry into the Reefer Madness Hall of Fame. Every argument that Baker, Healey, and Walsh make about marijuana could be made — with even greater force — about alcohol.

According to the National Institutes of Health:

-> Alcohol-related causes are the third leading preventable cause of death in the United States — killing almost 90,000 people per year;

-> Alcohol-impaired driving fatalities cause approximately 30% of all driving fatalities — over 10,000 deaths per year; and

-> Alcohol misuse problems cost the United States $223.5 billion per year.

Yet there is no call to ban the sale of alcohol. Governor Baker recently opposed an attempt simply to raise taxes on alcohol sales in Boston. And even Mayor Walsh, who often speaks publicly about his own experience with the dangers of alcohol, takes donations from that industry — raking in $1,400 from employees of The Boston Beer Company on a single day last November.

Why?

Because we have learned from painful experience that whatever harm is caused by the legal sale of alcohol, Prohibition is worse. Ban the sale of alcohol and it will be sold by Al Capone. Market share will be won and lost in a hail of bullets. Allow alcohol to be sold legally, and Budweiser’s talking frogs will duke it out with Coors’ Blue Mountains on Monday Night Football.

So too with marijuana. Indeed, as a recent article in the Washington Post recognized, “legal marijuana may be doing at least one thing that a decades-long drug war couldn’t: taking a bite out of Mexican drug cartels’ profits.” Far better that marijuana be sold legally, creating local jobs and tax revenues for the T, than go to fund death and destruction in Mexico and Central America.

Megan Krench and Joel Fleming live in Cambridge. Meg is a consultant who holds a Ph.D. in Neuroscience from the Massachusetts Institute of Technology. Joel is a lawyer and graduate of Harvard Law School.