To some commentators (David Bentley Hart and C.C. Pecknold, for example), there are fundamental and perhaps irreconcilable differences between libertarian politics and Christian convictions. One of the current controversies concerns proposals for the government to ban pornography. 

Pecknold made the case recently in the Catholic Herald, and he refers readers to Ross Douthat’s February 2010 New York Times proposal to ban pornography. According to social and religious conservatives, the libertarian exaltation — and I use that word deliberately —  of the individual and the conviction that people should be allowed to do Anything That’s Peaceful is at odds with individual and social flourishing.

Even if we assume pornography is an unalloyed bad, the case for banning it is pretty weak. Just as it’s a mistake to think that we will solve or even substantially reduce the problems stemming from alcohol, tobacco, and firearms by outlawing alcohol, tobacco, and firearms, we have to follow Thomas Sowell and ask, “And then what happens?” after we have made our policy that is supposed to fix a great social problem. Even if a ban accomplishes its intended consequences, we have to be mindful of the unintended consequences. When we change the rules, we change people’s incentives — and the unintended consequences of those changes can be worse than the problem we’ve set out to fix in the first place.

First, pornography is a very specific vice with a lot of evil substitutes. One of those substitutes is violence, sexual or possibly otherwise. There is evidence to suggest that the diffusion of pornography reduced divorce and rape, just as there is evidence that violent movies have been a substitute for actual violence. Obviously, this isn’t to suggest that pornography is good. Rather, it is merely to suggest that a liberal approach to pornography might be the least bad of our very imperfect options.

 Second, there is the intractable problem of definition. “I know it when I see it,” as Justice Potter Stewart said, is not a particularly helpful way to think about a standard for punishing vice. “Pornography” is in the eye of the beholder, and trusting lawyers and judges to define legal transgressions when no one is obviously violating another person’s rights lends itself to confusion and possibly arbitrariness.

Third, there are the resources people will inevitably waste trying to find ways to obey the letter of the law while circumventing its spirit. In 1999, a strip club in Casselberry, Florida, exploited a loophole in a public-decency law that exempted “bona fide” theatrical performances from prohibitions on nudity by staging a nude version of a scene from Macbeth (fair is foul, and foul is fair, indeed, methinks). How many serious crimes go unsolved every year because regulators, officials, and police departments get caught up in these endless cat-and-mouse games where a government passes a law, someone finds a way around it, a government passes a new law to “close the loophole,” someone else finds a way around that law, and so on?

Fourth, prohibition will drive pornography underground, where it will be provided by people with a comparative advantage in evil. Banning pornography would almost certainly increase illicit sex trafficking. California requirements that performers use condoms, for example, simply encouraged producers to move to other jurisdictions

The disasters that are alcohol and drug prohibition teach important lessons about policy failures. In 2008, the Institute of Economic Affairs in London published a volume of studies on Prohibitions and their unintended consequences You can download the PDF here. The volume even included a chapter on pornography by legal scholar and former ACLU president Nadine Strossen.

Finally, prohibitions require new rules and new organizations to enforce them. We might applaud them because they will be used to solve a well-defined and agreed-upon social problem, but we have to beware of the potential that these new rules and organizations could be used to suppress speech and expression of which the anti-pornography activists approve. 

This is more than a detail: power attracts people who crave it — or at least people who have no compunction about using it. It is rare to find an argument for prohibition that treats this seriously and soberly. Any plan — and prohibitions fall in this category — that only works if it is administered by the right people or that only works if people suddenly become significantly more moral probably won’t work as intended.

Keep in mind, too, that there is nothing new about the problem of suppressing vice in society. Thomas Aquinas provided the following answer: the attempt to use the law to create a society of perfect virtue risks creating even greater evils than the one you are suppressing. 

Sometimes, people use liberty badly. They buy, eat, and watch things that are bad for the body and bad for the soul. To paraphrase Sheldon Richman, however, just because some people cannot be trusted with liberty does not mean other people can be trusted with power. Even if pornography is a big social problem and even if we think government power can be a force for good, the case for pornography prohibition remains pretty weak: to “solve” one problem means creating a lot of other problems. This is yet another case in which it’s by no means clear that the cure is better than the disease.