When Pope Francis visits the United States next week, he is expected to meet with prisoners in Philadelphia and to address the criminal justice system in a speech to members of Congress.

Unfortunately, Pope Francis’ past comments in support of the drug war suggest that he will refuse to acknowledge one of the biggest contributors to American injustice and a primary reason why so many people end up in American prisons in the first place: drug prohibition.

In my book, After Prohibition, I quote a Catholic clergyman, Father John Clifton Marquis, who wrote:

Drug laws are a moral issue. Fifty years of drug legislation have produced the exact opposite effect of what those laws intended: the laws have created a tantalizingly profitable economic structure for marketing drugs. When law does not promote the common good, but in fact causes it to deteriorate, the law itself becomes bad and must change …. Moral leaders have no alternative but to choose between authentic morality, which produces good, and cosmetic morality, which merely looks good. Drug laws look good! But the tragic flaw of cosmetic morality, like all other forms of cosmetics, is that it produces no change of substance …. Authentic moral leaders cannot afford the arrogant luxury of machismo, with its refusal to consider not “winning.” Winning, in the case of drug abuse, is finding the direction and methods that provide the maximum amount of health and safety to the whole society without having a cure that is worse then the disease.

Father Marquis’s concern about the dangers of “cosmetic morality” in drug policy has been substantiated in the 25 years since he expressed it. Hundreds of thousands of people are incarcerated in this country for non-violent drug offenses. Countless innocent people, whether suspects, bystanders, or police officers have lost their lives in the name of prohibition.

And America’s drug policies have not just created these negative outcomes in America. Latin America, toward which the Pope has demonstrated a special affinity given his Argentine roots, has been for decades racked in the violence that inevitably attends the prohibition of such a lucrative market. Take Mexico, for instance. Although crime reporting is questionable in Mexico, estimates of the number of people killed in Mexican drug violence over the past decade range from 40,000 to more than 100,000 people. The entire drug corridor from the Andes to the United States has regularly been gripped by unimaginable violence, creating political and economic instability in addition to waves of drug war refugees.

On the other hand, we now have evidence that decriminalization and legalization are not the disasters that drug warriors insist. Portugal decriminalized all drugs in 2001. In 2008, Cato published a study of Portugal’s drug policy by Glenn Greenwald that found, in pertinent part, that:

[D]ecriminalization has had no adverse effect on drug usage rates in Portugal, which, in numerous categories, are now among the lowest in the EU, particularly when compared with states with stringent criminalization regimes. Although post-decriminalization usage rates have remained roughly the same or even decreased slightly when compared with other EU states, drug-related pathologies—such as sexually transmitted diseases and deaths due to drug usage—have decreased dramatically. Drug policy experts attribute those positive trends to the enhanced ability of the Portuguese government to offer treatment programs to its citizens—enhancements made possible, for numerous reasons, by decriminalization.

The empirical evidence supports Father Marquis’s position, and invalidates Pope Francis’s calls for the continued prohibition of drugs. Just as it did during the 1920s and 1930s, drug prohibition has proved to be a cure far worse than the disease.

Pope Francis is one of the most influential moral leaders in the world, but he needs to open his eyes to the misguided “cosmetic morality” that brings about so much harm.