The surprising decision of Spain, once the most Catholic country in Europe (except for Ireland), to recognize gay marriage‚Äîa decision that comes in the wake of a similar decision by Canada and, of course, by the Supreme Judicial Court of Massachusetts‚Äîpresents an appropriate occasion on which to consider what light economic analysis might shed on the issue.
Economics focuses on the consequences of social action. One clear negative consequence is the outrage felt by opponents of gay marriage and of homosexual rights in general. Philosophers like John Stuart Mill would not consider that such outrage should figure in the social-welfare calculus; Mill famously argued in On Liberty that an individual has no valid interest in the activities of other people that don't affect him except psychologically. (Mill had in mind the indignation felt by English people at Mormon polygamy occurring thousands of miles away in Utah.) But that is not a good economic argument because there is no difference from an economic standpoint between physical and emotional harm; either one lowers the utility of the harmed person.
The issue is more complicated to the extent that some of the outrage is based on fear that making homosexual relationships respectable by permitting homosexual marriage will encourage homosexuality. Most people don't want their children to become homosexuals, and this aversion is a factor in the utility calculus. However, they are probably mistaken in thinking that homosexuality is chosen; there is compelling evidence that sexual orientation is an innate (probably genetic) rather than acquired characteristic. It is not clear what weight, if any, society should give to opinions formed on the basis of scientific error.
Obviously there are benefits to homosexual couples from marriage‚Äîotherwise there would be no pressure to extend marriage rights to them. (Whether, given the alternative of civil unions, there are incremental benefits to marriage is a separate question that I discuss later.) Some of these benefits appear to impose no significant costs on others and thus are clear social gains: an example is that a married person does not have to have a will in order to bequeath his property at death to his spouse. Unless "outrage" costs are high, such benefits would, in an economic analysis, warrant recognizing gay marriage.
However, other benefits to married couples impose costs on third parties; an example is social security spousal and survivor benefits, to the extent they are not (and usually they are not) fully financed by the social security taxes paid by the person bestowing or obtaining the benefits. But such redistributive effects are equally imposed by heterosexual marriage, so they don't make a strong argument against homosexual marriage, especially since homosexual marriages are unlikely to be a significant fraction of all marriages. Only 2 to 3 percent of the population is homosexual and, judging from experience thus far, lesbians, who are far outnumbered by male homosexuals, seem much more interested in homosexual marriage than men are. Although I am not able to verify this figure, I believe that about two-thirds of gay marriages are lesbian, even though only about a third of homosexuals are lesbian. If this pattern persists, the total number of gay marriages will probably be very small relative to the number of heterosexual marriages.
The more fundamental economic question is why marriage is a legal status. One can imagine an approach whereby marriage would be a purely religious or ceremonial status having no legal consequences at all, so that couples, married or not, who wanted their relationship legally defined would make contracts on whatever terms they preferred. There could be five-year marriages, "open" marriages, marriages that could be dissolved at will (like employment at will), marriages that couldn't be dissolved at all, and so forth, and alimony and property settlement would be freely negotiable as well. The analogy would be to partnership law, which allows the partners to define the terms of their relationship, including the terms of dissolution. As with all contracts, the law would impose limits to protect third-party interests, notably those of children.
If outrage costs are set to one side, a purely contractual approach to (or replacement for) marriage makes sense from an economic standpoint because it would permit people to define their legal relationships in accordance with their particular preferences and needs. For those who did not want to bother to negotiate a "marriage" contract, the law could provide a default, one-size-fits-all solution‚Äîthe conventional marital status embodied in state marriage statutes. That would reduce transaction costs for those people content with the standard "form contract." The law would, however, have to decide what contractual relationships qualified for social security and other public benefits to which spouses are entitled under current law.
The contract approach to marriage may seem radical, but that is because of a lack of historical perspective. Marriage has changed enormously over the course of history. In many cultures, it has signified the purchase of a woman by a man's family. In other cultures, instead of brideprice, there is dowry (an approximation to the purchase price for a husband, paid by the wife's family.). Arranged marriages, often of children, have been common. Divorce at will by the man only has been common; likewise, of course, polygamous marriage (including in the Old Testament). Trial marriages, defeasible if the wife fails to become pregnant, were a Scandinavian institution. Shia law recognizes temporary marriages. "Companionate" marriage, in which husband and wife are expected to be best friends, is a modern institution. In short, marriage has changed greatly in history, and it would be foolish to think that the current marriage conventions will remain fixed for all time. With the rise of no-fault divorce, the enforcement of prenuptial agreements, and the decline of alimony, marriage is evolving in the direction of contract. That evolution has contributed to the movement for gay marriage. For, as marriage becomes more like a contract, it becomes harder to see why homosexuals‚Äîwho as I say are free to form other contracts‚Äîshould be excluded from its benefits.
Under a contractual approach, gay marriage as an issue would disappear, because the state would not be being asked to "recognize" gay marriage and by doing so offend people who are distressed by homosexuality. No one thinks that homosexuals should be forbidden to make contracts, and marriage would be just a contract so far as any legal consequences were concerned. It would be left to individual religious sects to decide whether to permit church marriages of homosexuals.
The most remarkable aspect of the current controversy is that it is mainly about a word‚Äî"marriage." The reason is that although most Americans still oppose civil unions (among American states, only Vermont and Connecticut authorize civil unions, though New Jersey authorizes a related arrangement called domestic partnership; a number of foreign nations now authorize civil unions, some under the name "registered partnership"), I imagine that if the homosexual-rights lobby dropped marriage from its agenda and put all its effort into lobbying for civil unions, many states would soon recognize them, and eventually the federal government would follow suit and grant parties to such unions the legal status of spouses for purposes of social security and other federal laws; when that happened, there would be no practical difference between civil unions and marriage. Why so much passion is expended over the word "marriage" baffles me. After all, even today, and even more so if civil unions were officially recognized, homosexual couples can call themselves "married" if they want to. And this brings to the fore the disadvantage of treating marriage as a legal status. Were it just a contract, government would have no role in deciding what word the parties could use to describe the relationship created by it.
Although personally I would not be upset if Illinois (where I live) or any other state decided to recognize homosexual marriage, I disagree with contentions that the Constitution should be interpreted to require state recognition of homosexual marriage on the ground that it is a violation of equal protection of the laws to discriminate against homosexuals by denying them that right. Given civil unions, and contractual substitutes for marriage even short of civil unions, the discrimination involved in denying the right of homosexual marriage seems to me too slight (though I would not call it trivial) to warrant the courts in bucking strong public opinion; and here it should be noted that although the margin in the polls by which homosexual marriage is opposed is not great, the opponents tend to feel more strongly than the supporters. Most supporters of homosexual marriage, apart from homosexuals themselves (not all of whom favor homosexual marriage, however), and some (not all) of their parents, support it out of a belief in tolerance rather than because of a strong personal stake, whereas many of the opponents are passionately opposed, some because they fear homosexual recruitment, contagion, etc., but more I think because they believe that official recognition of homosexual marriage would disvalue their own, heterosexual marriages.
Of course it is often the duty of courts to buck public opinion; many constitutional rights are designed for the protection of minorities. But when, as in this case, there is no strong basis in the text or accepted meaning of the Constitution for the recognition of a new right, and that recognition would cause a powerful public backlash against the courts, the counsel of prudence is to withhold recognition. Doing so would have the additional advantage of allowing a period of social experimentation from which we might learn more about the consequences of homosexual marriage. One state, Massachusetts, already recognizes homosexual marriage, as do a small but growing number of foreign nations (Spain, Canada, Belgium, and the Netherlands). Perhaps without judicial intervention gay marriage will in the relatively near future sweep the world‚Äîand if not it may be for reasons that reveal unexpected wisdom in the passionate public opposition to the measure.