It is often said, mostly by social liberals, that we should not attempt to "legislate morality." There are two major problems with this. In this, the first post on this subject, we'll deal with the more theoretical of the two. We'll handle the more practical consideration next time.
The first problem with the idea that we shouldn't legislate morality is this: that's exactly what legislation is. If there is no moral foundation for a law- if there are only "practical" considerations- then there is neither any basis for any specific law, nor are there any limits on what laws might be passed. If we're only looking at "practical" considerations, there is no reason that murder should be a crime, unless that specific murder can be shown to harm "society." So murdering a politician or high executive would be prosecutable while murdering a Hobo would not. Or, at least, one would carry a higher sentence than the other. Indeed, murdering Hobos might be shown to benefit society, inasmuch as it reduces their drain on society. On the other hand, there would be no reason that homosexual relationship could not be banned altogether, since they are completely incapable of producing offspring, and therefore "harm society" by not contributing to its continuation.
The list is endless. We could completely outlaw drinking, because drunkenness harms society, but any given instance of theft might have to be shown to harm society itself, rather than theft, in general, being harmful. We could completely turn our legal system upside down, and there would no philosophical or logical reason to oppose such a thing. Your mind is already coming up with rationalizations for why we would still outlaw theft and murder, while not outlawing booze or homosexual relationships. This is because the Moral Law is so deeply ingrained in you that you are loath to give it up, even as a theoretical exercise.
If we are going to have any security against government overreach, we must subscribe to the Moral Law, and attempt to preserve it in our legal institutions. As long as we do so, we receive the benefits of the Moral Law, including the limits it necessarily places on Government. For, while it is true that the Moral Law hates evil and loves good, just as the Creator does, because it stems from the nature of the Creator, it also values free will, and enshrines the ideas of personal responsibility and liberty. It does this, also, because it stems from the nature of the Creator- the same Creator who gave us free will and liberty, but constrained those by giving us personal responsibility as a counter-balance.
So we have a bargain. On the one hand, we can choose to reject the Moral Law, and never "legislate morality." If we choose that option, we have no reason to be self-conscious about our choices, or to feel guilt when we do things the Moral Law opposes, but we also lose any defense against an over-reaching, dictatorial government. On the other hand, we can choose to accept the Moral Law and legislate accordingly. If we do this, we do have to accept certain standards of behavior, but we also receive security in the knowledge that Government itself is constrained by that same Moral Law that restrains us, individually.
In Part II, we'll consider the more practical considerations.