MARRIAGE may be for the ages—but it changes by the year. And never, perhaps, has it changed as quickly as since the 1960s. In western law, wives are now equal rather than subordinate partners; interracial marriage is now widely accepted both in statute and in society; marital failure itself, rather than the fault of one partner, may be grounds for a split. With change, alas, has come strain. In the 25 years from 1960, divorce rates soared throughout the west—more than sextupled in Britain, where divorce appears inevitable for the world's most celebrated marriage, that of Charles and Diana Windsor. Struggling to keep law apace with reality, Britain's Tory government is even now advancing another marriage reform, seeking, on the whole sensibly, to make quick or impulsive divorce harder but no-fault divorce easier.

That, however, is not the kind of reform which some decidedly un-Tory people are seeking—and have begun to achieve. Denmark, Norway and Sweden now allow homosexual partners to register with the state and to claim many (though not all) of the prerogatives of marriage. The Dutch are moving in the same direction. In France and Belgium, cities and local governments have begun recognising gay partnerships. And, in the American state of Hawaii, a court case may legalise homosexual marriage itself.

As of today, however, there is no country which gives homosexuals the full right of marriage. And that is what gay activists in more and more places are seeking. Marriage, one might think, is in turbulent enough waters already. Can gay marriage be a good idea—now?

Home, hearth and health

To understand why the answer is yes, first set aside a view whose appealing simplicity is its undoing. “Governments are not elected to arrange nuptial liaisons, much less to untangle them,” writes Joe Rogaly in the Financial Times. “It is a purely private matter.” On this libertarian view, the terms of a marriage contract should be the partners' business, not the state's. With the help of lawyers and sympathetic churchmen, homosexuals can create for themselves what is in all practical respects a marriage; if they lack a government licence, so what?

The government-limiting impulse motivating this view is admirable. But, in truth, the state's involvement in marriage is both inevitable and indispensable. Although many kinds of human pairings are possible, state-sanctioned marriage is, tautologically, the only one which binds couples together in the eyes of the law. By doing so it confers upon partners unique rights to make life-or-death medical decisions, rights to inheritance, rights to share pensions and medical benefits; just as important, it confers upon each the legal responsibilities of guardianship and care of the other. Far from being frills, these benefits and duties go to the very core of the marriage contract; no church or employer or “commitment ceremony” can bestow them at one blow. If marriage is to do all the things that society demands of it, then the state must set some rules.

Just so, say traditionalists: and those rules should exclude homosexuals. Gay marriage, goes the argument, is both frivolous and dangerous: frivolous because it blesses unions in which society has no particular interest; dangerous because anything which trivialises marriage undermines this most basic of institutions. Traditionalists are right about the importance of marriage. But they are wrong to see gay marriage as trivial or frivolous.

It is true that the single most important reason society cares about marriage is for the sake of children. But society's stake in stable, long-term partnerships hardly ends there. Marriage remains an economic bulwark. Single people (especially women) are economically vulnerable, and much more likely to fall into the arms of the welfare state. Furthermore, they call sooner upon public support when they need care—and, indeed, are likelier to fall ill (married people, the numbers show, are not only happier but considerably healthier). Not least important, marriage is a great social stabiliser of men.

Homosexuals need emotional and economic stability no less than heterosexuals—and society surely benefits when they have it. “Then let them 'unchoose' homosexuality and marry someone of the opposite sex,” was the old answer. Today that reply is untenable. Homosexuals do not choose their condition; indeed, they often try desperately hard, sometimes to the point of suicide, to avoid it. However, they are less and less willing either to hide or to lead lives of celibacy. For society, the real choice is between homosexual marriage and homosexual alienation. No social interest is served by choosing the latter.

To this principle of social policy, add a principle of government. Barring a compelling reason, governments should not discriminate between classes of citizens. As recently as 1967, blacks and whites in some American states could not wed. No one but a crude racist would defend such a rule now. Even granting that the case of homosexuals is more complex than the case of miscegenation, the state should presume against discriminating—especially when handing out something as important as a marriage licence. Thus the question becomes: is there a compelling reason to bar homosexuals from marriage?

One objection is simply that both would-be spouses are of the same sex. That is no answer; it merely repeats the question. Perhaps, then, once homosexuals can marry, marital anarchy will follow? That might be true if homosexual unions were arbitrary configurations, mere parodies of “real” marriage. But the truth is that countless homosexual couples, especially lesbian ones, have shown that they are as capable of fidelity, responsibility and devotion as are heterosexual couples—and this despite having to keep their unions secret, at least until recently. Would gay marriage weaken the standard variety? There is little reason to think so. Indeed, the opposite seems at least as likely: permitting gay marriage could reaffirm society's hope that people of all kinds settle down into stable unions.

The question of children in homosexual households—adoption, especially—is thorny. That question, however, is mainly separate from the matter of marriage as such. In settling a child with guardians who are not the natural parents, the courts and adoption agencies will consider a variety of factors, just as they do now; a couple's homosexuality may be one such factor (though it need not, by itself, be decisive).

In the end, leaving aside (as secular governments should) objections that may be held by particular religions, the case against homosexual marriage is this: people are unaccustomed to it. It is strange and radical. That is a sound argument for not pushing change along precipitously. Certainly it is an argument for legalising homosexual marriage through consensual politics (as in Denmark), rather than by court order (as may happen in America). But the direction of change is clear. If marriage is to fulfill its aspirations, it must be defined by the commitment of one to another for richer for poorer, in sickness and in health—not by the people it excludes.