A response to someone about drugs and the relationship between a moral and legal framework:
You hinted at the main reason why libertarians are libertarians, and it exactly boils down to the moral justification for the use of force. Libertarians believe force is only justified in self-defense i.e. when force (or the immediate threat of force) is present. More concisely, libertarians are completely against the initiation of force. This ultimately stems from their belief in property rights, namely that people have a legal right to their body, and any elements of nature they ‘mix their labor with’, or any good they receive via exchange or gift.
Ultimately, though, whether or not you find something (whether it be a belief in property rights, a belief in the non-initiation of force, or something else) morally compelling is attributable to your epistemology. There are atheists who contend that you can argue for a ‘rational ethics’; that is, that people can argue about what is objectively morally right and wrong. There are also atheists who argue that humanity’s sense of ethics is merely a result of sociobiology, an objectively insignificant evolutionary result of the development of human societies. These people would fall in the group you mentioned, who think that there is no basis for objective morality, and that therefore what is right or wrong in one culture has no bearing on what is right or wrong in another. My boilerplate response to people who hold this view is to bring up past human atrocities such as Nazi Germany, or even hypotheticals such as slashing a baby across the face. Most people will not deny that these actions are inherently evil.
As Christians, we believe in a transcendent being whose very existence ascribes an objective moral ethic to our lives. Thus, we believe murder, adultery, jealousy, etc. are morally wrong for us, as well as for the next guy, regardless of his cultural background and upbringing. But, like you said, the real question is how to transcribe this sense of morality into a legal framework, in which we Christians are to live harmoniously with our fellow human beings, whether they are Christians or non-Christians, all while not violating our own Christian moral principles.
The key to answering this question is seeing the ethical judgement that is rooted in deeming something ‘illegal’. What does it mean to say action X is illegal? It means that if a person performs action X, the agency in society that is responsible for enforcing the law has a legal right to use force against that person to stop action X. The ethical judgement is precisely this use of force. Whether or not you’re a libertarian, using force against somebody must be justified. The libertarian says it is only justified when action X is itself invasive; that is, if the person performing action X is invading another person’s person or property.
So, it is clear that one’s ethical framework should not be equated with one’s legal framework. That is, we should not deem actions illegal just because we believe they are immoral. This is clear to most people in the context of sins such as jealousy, lust, and other ‘sins of the mind’. The use of force should not be permitted to stop somebody from thinking lustful thoughts. (If you think it should, then you have to justify this use of force on some grounds).
Then what criterion should we use, from a Christian perspective, for establishing the law? What is sufficient for declaring something illegal? It has to be something. And hopefully it is clear that it shouldn’t be our moral compass, since this involves the initiation of force (which I would argue is also part of a Christian’s moral compass). I think the libertarian answer is the most satisfactory, that we only use force when someone else has already used force (or is about to).
How does the libertarian principle stack up with our obligation to live moral lives as Christians? Well, living moral lives has to do with our own actions. The bible teaches us that individuals sin against the father, and that we ought to strive to sin less in our own personal lives. In other words, just because something is legal in a libertarian society, does not mean it is morally right. (Conversely, as already stated, the fact that something is immoral is not a sufficient condition for it being illegal). Thus, just because jealousy would be legal in a libertarian society, does not mean that I am morally justified in being jealous. Being a libertarian is different from being a libertine.
I’m sure you knew a lot of this, but I just wanted to state it clearly before coming full circle back to your original question. At the end of your email you said:
For me, my “moral position” on the matter is unchanged. I think drugs are bad. But the question is, what is the appropriate moral response?
So you see, the question for me is not what is the appropriate moral response. Because a moral response is different from a legal response. The moral response has to do with my epistemology as a Christian, which ultimately tells me that consuming drugs is objectively immoral. But does this mean they should be illegal? The personal moral answer should have no bearing on this question. If you say drugs are illegal, you are saying it is O.K. to use force against somebody to stop them from consuming drugs. I would argue that you then must justify why this use of force is acceptable. Rather, when posed with the question of whether or not the use of drugs should be illegal, my response would be that they should not be illegal, since their use does not invade any other person’s body or property.
This is the principle that I consistently apply to the law. In my opinion, it is the only legal principle consistent with the Christian worldview, as the use of force against another person is itself an immoral act.