Between social conservatives on the right and tobacco prohibitionists on the left, it sometimes seems as if everyone wants to impose his or her version of morality on everyone else. After all, if it makes sense to protect us from things like murder, assault, and theft, why shouldn't our representatives in government also protect us from other sinful or harmful activities like pornography and smoking? These self-righteous souls have a clear vision of the good life, and they want you and me to share that life, whether we like it or not. I don't know whether they have good intentions or not—whether they are motivated by a desire to help others or merely by a desire to control them, or by some combination of these and other impulses—and I don't much care. What matters is whether what they are saying makes sense, and whether the results of their actions are actually good. It doesn't, and they aren't.
Why doesn't it make sense to treat pornography and smoking the same way we treat murder, assault, and theft? Because these latter acts are clear instances of aggression by one party causing real, unquestionable harm to another's person or property. As actual crimes, they merit retaliation in kind, and the use of defensive force against the aggressor is justified. Pornography and smoking, however, are just as clearly not instances of one party initiating the use of force against another. As long as those who participate in these activities do so voluntarily, no retaliation by the government or anyone else is justified, period. (Of course, to the extent that it happens, forcing someone to participate in the production of pornography is a crime, just as it would be a crime to force someone to work in the tobacco fields.)
The worst that can be said of things like porn and cigarettes is that they are vices. Vices can harm those who partake of them, but they must also be pleasurablem or else no one would ever freely choose them. Those who would impose their version of the good life on others think they know for certain that the harms outweigh the benefits, not just for them but for everyone else as well. They also assume that those harms and benefits will net out the same for everyone, ignoring the simple fact that people are different. (At the extreme, anti-vice crusaders may believe that pleasure itself is actually bad, but I must admit I am stumped about how to address such a twisted notion! It's probably best just to reason with those who are less damaged.) What are the negative results of prohibiting vices? It a) empowers actual criminals by allowing them to profit from the black market in prohibited wares, b) exposes non-criminals to added risks, and c) wastes resources that could be used to fight actual crimes, or for some other purpose entirely. In trying to convince those who worry about vice to allow other individuals to weigh personal harms and benefits for themselves, we should try to redirect their attention to these very real harms stemming from prohibition itself.