Thornton is a believer in the Iron Law of Prohibition, which posits, according to Wikipedia, that restrictions and prohibitions of substances result in increasing potency of the banned products. One of the arguments for continued enforcement of laws against marijuana is that modern marijuana is much higher in THC content than the reefer that was around fifty years ago. If you are a smuggler, smaller amounts of more potent contraband are easier and more profitable to distribute.
The Daily Bell also asked why prohibition is so attractive to the ruling elites. Thornton replies:
The power to prohibit the consumption of a product gives the State an entry to controlling the production and consumption of just about anything. If the State can prohibit alcohol as a dangerous product, then it can prohibit dangerous books or anything else. This is what the ruling elites want. They don’t want restrictions on their power based on natural rights, the Constitution, or anything else. They have two weapons to destroy the concept of America and our rights. They use fear and “patriotism” against us.
I drink coffee. I don't drink alcohol at all any more. I never used tobacco. I quit smoking dope before I quit drinking. I can't remember the last time I took an aspirin or other NSAID. I have no use for drugs, except caffeine. But prohibition isn't about the drugs or the drink. It's about the control. I think prostitution is sick, and I certainly don't want to visit a prostitute or go to a strip club. I've never even been inside a Hooters and have no plans to go. I hate chicken. The difference between me and the prohibitions is not that I am immoral, and they are moral.
To stop prosecuting and giving the state power over the lives of people -- in effect, enslaving those who do things we think are wrong is not the same as approving those behaviors. The "slippery slope" is not toward permissiveness but toward collectivism and loss of freedom. Thornton explains the positive origins of rules and restrictions:
Well, it is basically that prohibitions in our daily lives are good things that we eventually recognize, as mature people, are good for us. I’m not talking about government prohibitions here. I’m referring to the rules that good parents require of their children. “You are not permitted to play until your homework is done and your room is clean.” It also refers to commercial rules such as “No shoes, no service.” Or it could be a rule that there is no smoking or talking on cell phones allowed at your place of worship. These prohibitions are easily enforced and benefit the greater good in many ways, plus they are voluntary in the sense that you choose either to smoke or to pray. Some people just don’t realize that such rules of conduct cannot carry over to the larger political society.Emphasis on that last sentence added by me. Rules and prohibitions are good -- so long as they are parental, individual, private, local, etc. It's when society takes a more general approach and decides to move personal and moral prohibitions to state and national laws that we get into trouble.
Libertarians are not anarchists. We don't need to do away with all laws. We do need to do away with a lot of them. No one is going to argue that theft, rape, and murder need to be legalized. All libertarians believe in the sanctity of private property. We obviously need, in a modern society, a legal system and statutes to protect property rights and to deal with thugs and psychopaths and the like. What we don't need are federal laws on the content of local school lunch menus or state laws prosecuting Christians for refusing to bake cakes or laws telling individuals what they can or cannot ingest on their own property.
Oh, but the prohibitions say, what about the people who get drunk in public and cause problems or drive under the influence? You can have laws against disorderly conduct or disturbing the peace, and we have traffic laws and laws to deal with those who act negligently and irresponsibly or maliciously to injure others or damage or destroy the property of others.
Prohibition is nearly as stupid as a hate crime law. Hate crime laws seek to punish thought crimes. Why not stick with punishing the behavior that you wish to have extinguished? Assault and murder can be illegal without making it about anything else, and we always take intent into account anyway.
Fewer laws and better laws and more agreement make for a better and more moral society. The proliferation of laws that have no solid moral basis along with inconsistent, often "class-based" enforcement (Kennedys) can cause a loss of respect for the law and a loss of clarity about what is right and wrong. Being legal does not making something right, ethical, or moral. And, sometimes, moral and righteous things are deemed illegal by an out-of-control police state.