Over here in Oregon we have a proposed (state) constitutional amendment called "Measure 36". It is basically the state equivalent of the FMA defining marriage as being between one man and one woman. This is a voter initiative and bypasses the legislature altogether (apparently it is legal to amend the state contitution by initiate in Oregon).
I was talking to one of my profs who shares a similar political outlook with me. He was surprised that I, as well as a couple of other of his students students, am against the measure. I, in turn, was surprised that he did not see things my way. I am of the "gay marriage is immoral but should be legal" camp, he is of the "gay marriage is immoral, should be illegal, but supports civil unions" camp.
He asked why I didn't support the amendment given that we both believe that gay marriage is immoral. I gave him two reasons.
First, I noted that not all immoral things are, or should be illegal. For example, worshipping other gods is Immoral, possibly the MOST Immoral thing you can do, according to the Bible. Yet the right to do so is enshrined in the 1st amendment. Why shouldn't gay marriage also fall into the same "immoral but legal" category as worshipping other gods.
My prof was shocked by this. He had apparently never thought about things this way. The idea that something could be immoral but yet legal, that the freedom to do wrong was a good thing, was completely new to him. Which surprised me because he is really a very thoughtful guy and this line of reasoning should not have been new to him. He admitted that this was a strong arguement.
My next reason was that I didn't approve of legislating morality. He immediately jumped all over me on that one saying that I couldn't really mean that. Our discussion of this was long and tortured, but I managed to finally clarify my position to say the following: in America, we should not pass laws where the primary concern is morality; we should only pass laws which have civil values as their primary concern. Civil values in this case are values which either ensure the safety/order of society (think traffic laws and zoning laws) or the more important values of freedom, democracy, life, liberty, etc. which are laid out in our Founding Documents (Constitution and Dec of Ind). Note: this latter category trumps the safety/order laws.
So this is what I mean by not approving of "legislating morality": our laws here in America should have primarily a civil function, not a moral function.
I have two basic reasons for holding this view. First, we live in a secular democracy. There is a supposed wall of separation between Church and State, and I think rightly so. (Church and State should only be united in a theocracy. America is not one of those and could not become one without fundamentally changing the character of the nation. However, in a theocracy, it would be appropriate to legislate morality.) As I think that morality without Christ is ultimately empty, then to legislate true morality would be to legislate Christianity, thus violating Church/State separation.
The second reason that legislating morality is a bad idea was summed up nicely by Jeremy in a comment in this post: "Seeking to mend the religious backsliding in the United States by this sort of method is idolatry. It's trying to get the government to cover over a moral problem by redefining it through political change rather dealing with the spiritual issues first." That is to say that legislating morality is an attempt to control behavior without dealing with the spiritual roots of the problem. Coming back to the gay marraige issue, I don't want gays to not get married because it is illegal, I want them to not get married because they don't want to, because they are following Christ. The legislation doesn't deal with the underlying issues at all.
Jeremy's response to this is quick: "My support for legislating morality is simply that we can't get rid of our laws based on morality, or we wouldn't have many laws worth much. Murder, breaking contracts, stealing, tax fraud, abuse of authority, maintaining a vehicle that badly pollutes, maintaining a plant that badly pollutes, polygamy, having sex with children, and racial discrimination are all moral issues. If we have to stop legislating morality, we have to get rid of all laws related to any of them."
My response: all of those examples are laws which have as their primary purpose a civil value. If murder was legal, then there would be chaos. There would be little safety or security and it certainly violates the value of 'life'. Yes they are all moral issues, be even when you disregard the moral merits of those laws, they are still beneficial to American society. Thus they are not "legislating morality". We would not need to "get rid of all laws related to any of them".