A third dodgy suggestion is that legalization — of marijuana only — would dramatically reduce violence in the U.S. and Latin America. Most prohibition-induced violence now stems from drugs other than marijuana, so this tactic makes the marijuana legalizers look uniformed or dishonest.

Still another bad defense of legalization is that marijuana is safer than alcohol or cigarettes. Regardless of the facts, this claim just spurs the prohibitionists to support bans on more goods. Plus, most of prohibition’s ills stem from prohibition, not the properties of the prohibited good.

Perhaps the worst argument for legalization is that use would not increase. Available evidence does not suggest a large increase, but lower prices and legal acceptance would certainly nudge in that direction. Legalizers should also reject the view that increased use is necessarily a bad or that reduced marijuana use is an appropriate goal for government policy.

So what argument should legalizers employ? That the government has no business interfering in private activities except to prevent harm to others. Concern for such “spillovers” might justify laws against driving under the influence or perhaps a minimum age of use. It cannot justify an outright ban of marijuana or even significant restrictions.

This defense of legalization has the enormous virtue of honesty, and it forces prohibitionists to admit that they do not support individual liberty. Some people share the prohibitionist perspective, but most do not. So legalizers should trust their fellow citizens and believe that, when honest arguments are made, the right side usually wins.

Jeffrey Miron is senior lecturer and director of undergraduate studies at Harvard University and Senior Fellow at the Cato Institute. Miron is the author of Libertarianism, from A to Z and a member of Expert Insight.