I already brought up the difference between civil and religious marriage in a previous post. In this case, it seems key to understand what are the limits of the civil interest in regulating marriage and what are the rightful province of religious law.
If we take the most traditional marriages as a basis upon which everyone can agree, we can enumerate some properties of marriage in which there is a clear civil interest. The definition of joint property rights. Joint responsibility for children and for one another. A legal status which creates special status with regards to coinsurance, medical visitation rights, and so on. The conditions under which a marriage may be dissolved, either with cause or by mutual consent. (Note that these have the structure of an area of traditional contract law!)
We can also take a known difference in cultural marriage laws - say, the difference in divorce laws between Catholics and Protestants - to understand some of the boundaries which the civil law should not cross. The Catholic law defines a much more restrictive set of rules under which the contract can be dissolved. To find the boundary, consider the cases under which the civil law and the Catholic law may come into conflict: (1) If both parties are Catholic and agree to submit to Catholic religious law, the more stringent provision of that law clearly ought to dominate. (2) If only one party is Catholic, and the other party is (say) Protestant, there is not a religious court of mutual consent, and then the civil law must take over by default. Since we are discussing the rules for the severance of a contract, we should also consider (3) Both parties were Catholic at the time of the marriage, but since then one party has left the church. In this case we are in a situation similar to that of (2), since there is no religious court of mutual consent.
Clearly the question is whether the civil law ought to override the religious law in cases (2) and (3). Based on the principle of civil law - that it exists (among other things) to adjudicate conflicts between members of different groups on the basis of the least principles of common agreement - the answer is clearly yes. The next question is therefore what the specific civil law ought to be.
Since the marriage contract is a symmetric one and an ongoing agreement, one expects that it must require mutual consent of the parties to maintain. If one party wishes to terminate the contract and the other does not, or if the contract is terminated "with cause," either party or both may have certain responsibilities to the other to "clean up" any remaining obligations created during the term of the contract, for instance an obligation to child support.
From such arguments it is apparent that the civil law of marriage is in essence a subset of the law of civil contracts. A civil marriage may be defined as a contract entered into by two people entailing certain minimal obligations to one another; a religious marriage is obviously much more than that, entailing emotional requirements, religious requirements and so on, but it is not the domain of the civil law.
Now let us consider the question of gay marriage. The question is essentially one of limiting which groups of people may enter into a contract of marriage. If marriage is considered purely as a contract between two people, clearly the only restriction would be that the two people be legally competent to contract; however, there are other issues, since many aspects of law and public policy refer directly to the existence of a marriage contract. On this basis, there is a prima facie case that the government should have a right to regulate who may enter into such contracts; for instance, incestuous marriages may be forbidden on grounds of public health (keeping the gene pool stable and all that), and corporate persons (as opposed to natural persons) may not marry.
In this specific case, we see that there are different religious groups with different opinions on whether homosexual couples ought to be allowed to marry. (Of course, different religious groups have different rules on who may marry far beyond this. Many groups prohibit marriage outside their religion; some groups have far more stringent rules on consanguinity than the civil law prescribes; some religious groups prohibit miscegenation. Clearly the religious definitions of what constitutes a legitimate marriage do not need to be the same as the civil ones!)
The question is whether there exists a compelling state interest in prohibiting two men or two women from entering into a contract of marriage. The state interests in such a regulation can come in two forms: if either (1) in some way such a condition would directly threaten the public order, or (2) it would indirectly threaten the public good, in this case by its effects on the other existing laws which directly or indirectly reference marriage contracts and so would be affected by such a decision.
To the first, I believe it is safe to answer "no" simply by the conservative principle of civil law. Reasonable people are known to disagree on the subject, suggesting that it would be an appropriate matter for religious law rather than civil; there is furthermore no obvious disturbance to public order, since this is highly unlikely to interfere with the ordinary course of commerce or lead to gunfights in the streets.
To the second, in order to answer affirmatively it would be necessary to show that a gay marriage would place an undue burden on the civil society, and that this burden would be substantially in excess of the costs imposed by enjoining a group from entering into a certain type of contract. I have heard no such argument made, nor (on the basis of what I know) does there appear to be any such argument to hand.
On this basis, I would conclude that there is no reason for the civil law to prohibit homosexual couples from marrying. Such a restriction, indeed, would appear to be the adoption of an individual group's religious law into the civil law, precisely the type of action which risks the greatest injury to the notion of civil law as a whole.
Therefore on the basis of civil law, I argue: The civil law ought to permit homosexual marriages. Indidivual groups (religions, etc.) are as always completely free to prohibit them within their own communities, and the civil government does not have the right to force these groups to recognize such marriages. (Up to the usual caveats about public order etc.) The law ought therefore to be precisely parallel to the law about interracial marriages; there is no compelling civic interest in prohibiting such a thing, and while individual groups may consider them unspeakable, that's simply not a matter for the civil law. People are free to dislike whatever they choose, but they are not free to require others to abide by their own tastes.
The next post will discuss a much more complicated issue: abortion. (And this one is going to take a while to write, so it won't be anytime soon!)
