Many libertarians argue that we should legalize recreational drugs in the name of freedom and personal autonomy. Drug prohibition, they argue, infringes on personal freedom by denying individuals the liberty to do what they want with their own bodies.

This is mistaken. In fact, it is drug legalization that infringes on freedom. Drug prohibition, not legalization, is the real pro-liberty position.

Let me explain.

The Foundations of Freedom

All should agree that one of the essential responsibilities of government is to protect and promote personal freedom. To that end, governments have an interest in restricting activities that impair, destroy, or otherwise undermine personal freedom.

Now, freedom cannot flourish unless certain background conditions are met. Consider an analogy with markets. If a government wants to protect and promote markets, then it must safeguard the conditions that make a market economy possible. These conditions include the protection of life, exchange, contracts, and private property. Without these prerequisites in place, it would be all but impossible for markets to flourish.

The same is true of freedom. If the government has a responsibility to protect and promote freedom, then it must also protect and promote the conditions that make it possible. On this point, one essential ingredient of personal freedom is rationality. Choices can only be free if they are made by a person whose cognitive faculties are functioning in the right way. Reason confers on our actions a certain order and intelligibility that make them explicable and coherent. It is what makes our actions ours, such that we are responsible for them. Our ability to act freely is diminished or destroyed if we are unable to deliberate and think coherently, or if we are subject to overwhelming coercive forces.

In other words, freedom isn’t just the bare ability to do something; it is the ability to act under the influence of properly functioning cognitive faculties. This point is pivotal in making sense of the legal concepts of consent, coercion, and competence. Young children are unable to enter into legally binding contracts because their cognitive capacities are not fully developed. Likewise, insanity defenses are based on the understanding that cognitively disabled or insane persons cannot be held criminally liable for their actions. There cannot be freedom without rationality.

Accordingly, since the government has a responsibility to protect personal freedom, it must also protect and promote a culture that is conducive to clear thinking and discourages impaired thinking. The government, therefore, has a responsibility to restrict activities that impair, destroy, or otherwise undermine clear thinking.

Recreational Drug Use Undermines Freedom

Recreational drug use interferes with clear thinking. The very activity is centered around the consumption of an intoxicating substance that impairs one’s cognition. The whole point is to impair one’s ability to think clearly, which in turn impairs one’s ability to act freely. Thus, recreational drugs should be legally restricted because their use is incompatible with the vision of a freedom-respecting liberal state.

There are two ways in which drugs affect cognition. First, there are the immediate effects of consuming certain drugs. The immediate effects of hallucinogens such as LSD and PCP include rapid mood swings, delusions, hallucinations, paranoia, and a distorted sense of time and self. Heroin produces euphoria followed by nausea and clouded mental functioning. The immediate effects of marijuana—which is often heralded as a “safe” drug—include anxiety, dysphoria and paranoia, altered judgment, cognitive impairment, and psychomotor impairment.

Second, there are the long-term effects of drug use. Many drugs have addictive effects that impair the freedom of drug users by exerting a powerful influence over their future actions. Drug addicts who become physically and psychologically dependent on drugs have their sense of self-control diminished or even destroyed. These addictive effects can bleed into other areas of an addict’s life, affecting his ability to work, learn, care for himself, interact with others, and form relationships. They may impel him to act destructively in order to fuel his addiction, thereby affecting the freedom of others besides himself.

Opponents of drug legalization typically focus on the long-term effects of drug use and their spillover effects to third parties, specifically children and teenagers. These are very serious concerns, to be sure, but the immediate effects of drug use are by themselves enough to show that recreational drug use is intrinsically antithetical to the good of freedom and personal autonomy. The opponent of legalization need not appeal to third party spillover effects to make his case.

Let’s sum up the argument so far. One of the government’s chief responsibilities is to protect and promote freedom. In order to do this, it must also protect and promote the underlying conditions that make freedom possible, one of these being clarity of thought. The government therefore has an interest in cultivating a culture that encourages clear thinking and discourages impaired thinking. Since recreational drug use impairs the user’s ability to reason, governments should therefore enact legal restrictions on recreational drugs.

In other words, if you value freedom, then you should oppose the legalization of recreational drugs.

Drug Prohibition: Myths and Realities

So far I’ve been defending drug restrictions. But the term “restriction” is vague. What kind of restrictions should the government adopt?

Answer: the government should prohibit those substances that have no legitimate use aside from recreation. In addition to making them difficult to obtain, prohibition serves to drive up the cost of drugs, which in turn reduces demand by making it more expensive. It’s simply a matter of supply and demand: the more expensive you make something, the less willing people are to buy it. The added threat of legal punishment also serves to drive down demand. Conversely, if something is cheap, legal, and widely available, then people are more inclined to buy it.

Drug legalization would make drugs both cheaper and more available, which in turn increases use. A 2015 study in the Journal of Health Economics found that medical marijuana laws increase marijuana use in both adults and adolescents. In adults aged 21 and older, the frequency of binge drinking also increased. Similarly, a 2017 study published in JAMA Psychiatry found that “medical marijuana laws appear to have contributed to increased prevalence of illicit cannabis use and cannabis use disorders.” Increased availability is also associated with increased use of other drugs, including alcohol.

Prohibition makes drugs more expensive and less available, which in turn reduces drug use. Alcohol prohibition, which many think ended in failure, actually reduced per capita alcohol consumption by about 30 to 50 percent. Cirrhosis death rates, admissions to state mental hospitals for alcohol psychosis, and arrests for drunk and disorderly conduct also declined dramatically. While is true that alcohol prohibition did ultimately fail, it failed for political reasons. In terms of reducing alcohol use, prohibition was a success. And given that excessive alcohol consumption impairs clear thinking (in addition to the $250 billion annual cost that it imposes on the nation), it is worth asking whether we should bring back some form of stringent alcohol regulation for reasons considered earlier.

Of course, not all drugs are used recreationally. Alcohol can be consumed as a mild social lubricant without the intention to get drunk. But this is not true of marijuana, as the whole point of non-medical marijuana use is to get high (and, as we will see, most cases of so-called “medical” use are indistinguishable from recreational use). Nobody smokes a joint wanting to avoid the high. So too with heroin, cocaine, and other drugs. These drugs would be the target of prohibition, since their paradigmatic use is abuse, unlike alcohol.

It is true that there will still be some who will go through the effort to illegally obtain drugs even if prohibition is enacted. Perfect compliance, however, isn’t the standard of success when it comes to lawmaking. Laws against murder, assault, and theft don’t stop all of these crimes, but nobody is proposing that we legalize these things.

Where Libertarians Go Wrong

Where many libertarians go wrong in their support for drug legalization is in their conception of freedom. If we think of freedom as just the bare ability to make choices, then it is understandable why one might think that drug restrictions infringe on personal freedom, since such restrictions do limit our ability to make a range of choices.

But not all choices are worth respecting. As I noted earlier, we cannot respect freedom without also respecting the conditions that make freedom possible. One such condition is the preservation and maintenance of properly functioning cognitive faculties. The free choices we should respect, therefore, cannot seek to undermine this condition. Since recreational drug use seeks to undermine clear thinking, the choice to partake in such an activity should not be respected.

This is not, as some liberal political theorists might object, to adopt a “moralized” conception of freedom. Rather, what is being appealed to are structural conditions needed to make sense of respecting freedom under any conception of the good life.

Indeed, it would be bizarre to argue that the state’s goal of promoting freedom is served by allowing its citizens to impair their own freedom. The initial decision to engage in recreational drug use may be free, but the end result is the diminution of freedom. One cannot realize his freedom by suppressing it, any more than one can become healthy by becoming ill. The idea that recreational drug use can be justified by an appeal to freedom or liberty is thus self-defeating in the same way that drinking seawater to remedy thirst is counterproductive to its own goal.

Some argue that there is a moral right to use drugs that is derived from our right of ownership over our own bodies. According to libertarian philosopher Michael Huemer, “it is hard to see how anyone who believes in rights at all could deny that . . . drug use, considered merely as altering the user’s body and mind, is an example of the exercise of one’s rights over one’s own body and mind.”

There are numerous problems with Huemer’s argument. For one, it does not follow from the fact that one owns himself that his rights over his own body are absolute and unlimited. Many philosophical traditions have held that we have duties of self-respect to ourselves, such as duties to preserve our own health and personal integrity, and to develop our talents. If there are such duties, then they would seem to count against a moral entitlement to debase one’s cognitive functioning. Appeals to bodily autonomy hinge on the background moral theory we adopt, and Huemer’s conception of self-ownership is no different. Huemer presupposes a controversial philosophical anthropology that needs to be justified, and he does not give us any reason why we should accept it.

Nor will it do to argue, as some libertarians do, that the defender of drug prohibition must also be committed to bans on fatty foods, soft drinks, and the like. The argument I have given here pertains only to activities that are intrinsically destructive to clear thinking, which unhealthy foods (which typically are only unhealthy when consumed excessively) do not affect. So this objection simply doesn’t apply.

What about Medical Marijuana?

My focus has been on recreational drug use, but it is worth briefly discussing so-called “medical” applications of drugs (specifically marijuana), since these are wedge issues that many pro-legalization advocates exploit to sneak in full recreational legalization.

There is research showing that cannabis or cannabinoids can help with pain management, nausea and vomiting, and multiple sclerosis spasticity. However, this same research has also found strong evidence that cannabis or cannabinoids can negatively affect respiratory health, lead to the development of schizophrenia or other psychoses, and increase one’s risk of being in a motor vehicle crash. So the putative benefits of marijuana must be weighed against the negative health effects of marijuana use.

Additionally, there isn’t really an essential need for medical marijuana, given that there are plenty of other medicines that can address the ailments that marijuana may help with. Thus, while I am open in principle to allowing certain kinds of medical marijuana (provided that it go through the same rigorous process by which other medicines are approved), it would appear to be unnecessary. And, given the health risks of marijuana, it would be ill-advised and reckless to legalize marijuana under the guise of medicine.

Indeed, medical marijuana is ripe for abuse. In states with medical marijuana programs, the overwhelming majority of medical marijuana users are young male adults who claim “pain” as the reason for which they need marijuana. Only a tiny percentage use marijuana for other reasons. Pain, of course, is a very vague reason that is easy to fake, so it provides an avenue for recreational users to obtain marijuana under the false banner of medicine. It seems then that medical marijuana programs provide a smokescreen for recreational use that amounts to de facto legalization. So there is a case to be made for extending drug prohibition to so-called medical marijuana.

The Bottom Line

To be clear, the argument I’ve offered here is not that recreational drug use should be restricted because it is unhealthy or immoral. Rather it is that recreational drug use impairs and undermines the conditions for freedom, and so the legalization of recreational drugs is incompatible with the vision of a freedom-respecting state.

As John Stuart Mill said, “the principle of freedom cannot require that [one] should be free not to be free. It is not freedom, to be allowed to alienate his freedom.” A society that values freedom must cultivate a culture that encourages clear thinking and discourages impaired thinking. For that reason, recreational drugs should be legally prohibited. Libertarians, therefore, should stand opposed to drug legalization.

This article is adapted from the journal article “Why Recreational Drug Use is Immoral,” which is forthcoming in The National Catholic Bioethics Quarterly.