An old post from about three years ago that bears reposting in the current climate.
Libertarians often argue that drug legalization would not lead to increased drug use. I find that preposterous, and you should too. There are at least three groups of people who are dissuaded from drug use by its being illegal.
1. There are those who respect the law because it is the law. 'It's against the law' carries weight with them; it has 'dissuasive force.' For these people the mere fact that X is illegal suffices for them to refrain from doing X. It doesn't matter for the purposes of my argument how many of these people there are or whether they are justified in respecting the law just because it is the law. The point is that there are such people and that the mere illegality of doing X supplies a motive for their not doing X.
Now suppose the legal prohibition on doing X is removed. Will every one in this first class begin doing X? Of course not. The point is that some will. So it should already be clear to anyone with common sense and no ideological axe to grind that drug legalization will lead to increased use.
2. There are those who may or may not respect the law because it is the law, but fear the consequences of getting caught breaking it. These people don't like rude encounters with cops, jail time, fines, loss of reputation, etc. Among these people are libertarians who favor legalization and have no respect for current drug laws but obey the current laws out of fear of the consequences of breaking them.
3. There are also those who are quite confident that they can avoid the consequences of breaking the drug laws, but fear the consequences of contact with drug dealers. They fear being cheated out of their money, being given diluted or poisoned product, etc.
Now take the logical sum, or union, of the three classes just menioned. The membership of that union is significant. Legalize drugs and some of those people will begin using drugs. And of those who begin, some will end up abusing them, becoming addicted, etc.
Therefore, it is utterly preposterous to claim as libertarians typically do that drug legalization will not lead to increased use. So why do people like Ron Paul make this claim? It is hard to figure. Why say something stupid that makes your case weaker than it is? Is it just knee-jerk oppositionalism? (I can't find my old post on knee-jerk oppositionalism, but I'll keep looking.)
Why did Paul say, "How many people here would use heroin if it were legal? I bet nobody would."? That's just a dumbass thing to say. Paul is assuming that whether one does X or not has nothing to do with whether X is legally permissible or legally impermissible. He is assuming that people who use drugs will use them no matter the law says, and that people who do not use drugs will refrain from using them no matter what the law says. That is a bit of silliness which lies beneath refutation. So again I ask: why do libertarians maintain extremist stupidities when there are intelligent things they can say?
After all, libertarians do have a case. So my advice to them would be to concede the obvious -- that legalization will result in greater use -- and then argue that the benefits of legalization outweigh the costs. They will then come across, not as fanatical deniers of the obvious, but as reasonable people who understand the complexity of the issue.
As for Ron Paul, I'm afraid he has already blown his 2012 chances with his remarks on heroin. It's too bad. The country needs to move in the libertarian direction after decades and decades of socialist drift. But the American people do not cotton to fanatics and the doctrinaire.