Through it all, seekers favoring calm and compromise have held to what they see as a middle way. Why insist on gay marriage, with all the religious and cultural baggage that the word “marriage” carries? Instead, give gay people some of the legal benefits of marriage, maybe eventually all of the benefits, but under separate statutes. John Kerry, the Democratic presidential nominee, spoke for much of the country when he said he opposed gay marriage but favored civil unions. Here, surely, was a way out … Right?

Alas, no. The proponents of civil unions deserve all praise for their effort to accommodate the very real legal needs of committed same-sex couples; and certainly, from a gay point of view, partner programs are much better than nothing. But think for a moment about the photos streaming back from San Francisco, photos showing the unbridled joy gay couples took in getting married–not civilly united, but married. No similar euphoria or outrage greeted Vermont’s landmark approval of civil unions in 2000. The newlyweds in San Francisco and their family and friends, and the San Francisco drivers who honked in support or yelled in derision as couples emerged from city hall, and, for that matter, everyone who saw the images on TV–all felt instinctively and powerfully that there is something special, something unique, about marriage.

Their feeling was correct. There is no substitute for marriage, and trying to concoct one is a hazardous business. Civil unions and other forms of non-marital partnership cannot give gay couples the essential social benefits of marriage, even if the legal benefits are comprehensive. Conservatives may argue that allowing gay marriage endangers matrimony for straights; in fact, creating alternatives to marriage, such as civil unions, is far more likely to undermine the institution of marriage. Both for gays and for society, only marriage will really do. Only marriage is marriage.

For most people, marrying, especially for the first time, is a very big decision. Not for everyone: Some people exchange vows in Las Vegas as a lark. But for most, getting married is a life-changing event, one which demarcates the boundary between two major phases of life. Why should marrying be such a big deal? Partly because the promise being made is extraordinary. That answer, however, begs the question. Why do people take this promise so seriously? The law has made it ever easier for two people to marry, no questions asked, no parental approval needed, no money down. Divorcing is easier, too. Under today’s laws, young people could casually marry and divorce every six months as a way of shopping around, but they don’t. Most people can expect that marriage will result in parenthood, and parenthood is certainly a momentous thing. Yet even people who, for whatever reason, do not want or cannot have children take marriage seriously. So the questions remain. Why do we see marrying as one of life’s epochal decisions? What gives the institution such mystique, such force?

When two people approach the altar or the bench to marry, they approach not only the presiding official, but all of society. They enter into a compact not just with each other but also with the world, and that compact says: “We, the two of us, pledge to make a home together, care for one another, and, perhaps, raise children together. In exchange for the caregiving commitment we are making, you, our community, will recognize us not only as individuals but also as a bonded pair, a family, granting us a special autonomy and a special status which only marriage conveys. We, the couple, will support one another. You, society, will support us. You expect us to be there for each other and will help us meet those expectations. We will do our best, until death do us part.”

In every marriage, social expectations are an invisible third partner. Friends, neighbors, parents, and in-laws heap blessings and congratulations on newlyweds, but their joy conveys an implicit injunction: “Be a good husband or wife. We’re counting on you.” Around the pair is woven a web of expectations that they will spend nights together, socialize together, make a home together–behavior that helps create a bond between them and makes them feel responsible for each other. (“It’s one a.m. Do you know where your spouse is?” Chances are you do.) Each spouse knows that he or she will get the first phone call when the other is in trouble or in need, and each knows that the expected response is to drop everything and deal with the problem.

A wedding is not just a social occasion; it is a whole social technology. A few people (my sister, for one) hold private weddings with, at most, a handful of guests, but even the most private wedding involves not two people, but three. Two people cannot marry each other; they must marry before a member of the clergy or a magistrate or clerk–someone to be the eyes and ears of society. In that sense, all weddings are public. If two people say their vows in the forest, with no one else around, they are not really married at all. Most weddings, of course, are not just public ceremonies but major events as well. The most important people in the partners’ lives–their families above all–are invited, and many of them come, sometimes traveling across the country or the world. The partners want to affirm their commitment not just in each other’s eyes but also in the eyes of the people who matter most. Each implicitly says to the other: “All of these people–my family, my friends, and your people, too–have heard my vow. That tells you I meant what I said.” Often, though, it is the parents, especially the mothers, who want a really big wedding. The pride they express in their children’s matrimony is another subtle–maybe not so subtle–way to say, “We have a stake in this union, too.” A hundred witnesses, five hundred, they all hear the couple express their commitment. The presence of the guests, their joy, their smiles and snuffles, stamp the day as a rite of passage. The vows are sealed by the tears of the mothers in the front row, tears that tell the couple and the world, “This promise is important. This promise is like no other.”

After the wedding come countless smaller gestures of community recognition and community interest. From now on, invitations arrive addressed to two people, not just one. Polite people do not neglect to say, “Give my best to your husband” or “How’s the wife?”–casual reminders that, in the world’s eyes, you’re attached to somebody. If things go badly, expressions of concern and sometimes gossipy chitchat (“Why does she put up with that cheating bastard Frank?”) quietly reinforce the community’s stake. Anniversary parties bring together friends and family to celebrate that the marriage is intact (no awkward questions asked). The magic of marriage is that it wraps each partnership in a dense web of social expectations, and uses a hundred informal mechanisms to reinforce those expectations.

Why the elaborate web of rituals and expectations? Why turn marriage into the Brooklyn Bridge of social engineering? The answer isn’t obscure. Committing to the care and comfort of another for life is hard. Some couples can stay in love romantically forever, and good for them. Some couples find that devotion and self-abnegation come easy. For most ordinary mortals, however, love and altruism aren’t always enough. Community begins where love leaves off. Community–our desire not to disappoint our parents and in-laws and friends, our hunger for status, our concern for reputation–can never make marriage easy; but, for many of us, it does make marriage easier. It reminds spouses, during the rough patches, of what they mean to each other, by reminding them of what their marriage means to the people who love them. That is why it is entirely appropriate that married people enjoy special social standing. They are doing something difficult, and they are doing it not only for their own sake and their children’s, but for the good of the community. The community owes them a debt.

To work best, marriage needs to be understood as a special commitment and a distinct phase of life. Brides and grooms must feel that when they say the vows, they are not just reciting poetry but crossing a boundary. To achieve that effect, marriage needs clarity, uniqueness, and universality. We can’t confer a special status on marriage unless we know who is married. We can’t preserve marriage’s mystique if marrying is just one of many arrangements people make to express their fondness for each other or to link their bank accounts. And we can’t preserve marriage as a norm if only some people can marry. If you want to damage marriage, then blur its boundaries, surround it with competitors, and riddle it with carve-outs and exceptions. While you are at it, unbundle the rights from the responsibilities. Give some people the prerogatives of marriage without asking them to make the Big Commitment, and give other people the burdens of marriage without giving them its special status. Which brings us to marriage-lite.

Domestic-partner programs, as they are generically called (although the ones that more closely resemble marriage are often called civil unions), are hard to generalize about, because they can take many forms. That, in fact, is one of the problems with them, and is a key way in which they differ from matrimony: Whereas civil marriage is a standard package whose terms are well understood and widely accepted, a domestic-partner program can be anything its sponsor says it is.

Who qualifies as a partner, as opposed to, say, a roommate? There is no standard definition. To cope with that problem, two states and more than 50 cities and counties have established some kind of domestic-partner registry. In some cases–not all, since, again, there is no standard–the registries “allow same-sex couples to obtain certain rights and benefits traditionally associated with marriage, such as hospital and jail visitation, child-care leave, and certain parental rights,” reports the Human Rights Campaign. Employers may choose to accept public registration, where available, as proof of being coupled, and they can also set terms of their own. Vermont and California have enacted broad partner programs that look a lot like marriage, although they confer none of the many federal benefits. Like marriage, these state-recognized unions can be fairly hard to get out of, requiring divorce proceedings. On the other hand, many partner programs can be terminated virtually at the drop of a hat, sometimes on the say-so of only one partner. Until California reformed its program recently, either party could unilaterally mail in a form saying, “I, the undersigned, do declare that Former Partner_______ and I are no longer Domestic Partners.” No fee, just use certified mail.

So there is quite a spectrum. Marriage-lite can be a lot of things. The one and practically only thing it reliably is not, indeed, is marriage. However close a domestic-partner program may come legally, it is no substitute for the genuine article. That is because marriage is more than a package of benefits that happen to have been bundled together for convenience’s sake. It adds value by bringing to bear the weight of social expectations that to marry is to commit. Everyone knows to expect married couples to be there for each other. Will people know what to expect of a domestic partnership, that newfangled invention of political activists and human-resources departments? Marriage-lite may have all of the bonding power of marriage, or it may have only some, or it may have none, depending on how seriously society and the partners take it. For myself, I cannot imagine my mother sobbing with joy and relief as she says, “Thank goodness, Jon has finally found a domestic partner.”

Civil unions do, of course, appeal to a wide variety of groups. Many moderates and liberals support domestic partnership programs, not because they oppose gay marriage, but because they worry that the country may not be ready to embrace it, especially in a presidential election year. Many also see civil unions as a way station en route to gay marriage. I have some sympathy for their position. If the only two choices were between domestic-partner programs for gay couples and nothing at all, I would certainly take the domestic-partner programs. But I make this statement with trepidation. For gay people, civil unions and the like are a seat at the back of the bus, a badge of differentiation and inferiority pinned on every same-sex union.

Moreover, moderates who embrace civil unions as a compromise position are probably also failing to consider how the ABM pact (Anything But Marriage) will backfire–is in fact already backfiring–against marriage. Indeed, there is another group that supports civil unions in part because they understand how such halfway designations have the potential to undermine the unique status of matrimony. They are no friends of marriage. They view it as stifling if they are libertines, archaic if they are radicals, patriarchal if they are feminists, and often as all of the above. Most of them would say marriage takes much too narrow a view of what constitutes a family. The privileging of marriage–the special standing marriage enjoys–is precisely what they oppose. The alternatives-to-marriage movement wants the government to stop picking and choosing among relationships and lifestyles, and it views domestic-partnership programs–for gays and straights alike–as a foot in the door. Instead of having to decide whether to jump across a boundary society sets for you (marriage), what if you could just pass from one sort of arrangement to the next, with society adjusting to whatever boundaries you set as you go along? Wouldn’t it be nice if there were a halfway house? A way to get health insurance without having to say “till death us do part”? Actually, a lot of people, gay and straight, would like a halfway house: or, to be more blunt about it, a free ride. Throughout most of history, society has been smart enough to deny it to them.

Civil unions would not pose such a threat to marriage if domestic-partner benefits were limited to homosexuals, who, after all, can’t marry. The benefits should be so limited. The question is: Can they be? The answer is, generally, no. Say you are a corporate human-resources executive. Your business has established a domestic-partner program for gay employees. One day you receive a delegation of straight workers, maybe under the auspices of the union. They say they have partners but happen not to be married. They want partner benefits, too.

You’re right, of course. But you already sense you’re on thin ice. The answer–you can see it coming–is indignant: “Who are you to tell us how to run our personal lives? You mean that, to get equal treatment, we have to sit here and explain the many good reasons why we have chosen not to marry? Since when did working here mean letting you invade our privacy and judge our relationships?” You can see where this conversation goes. Gays lose partner benefits or, more likely, straights get them.

Matters are no different in the public sector. Politicians follow the votes, and most of the votes in America belong to heterosexuals. When gays get a benefit, straights want it, too, and there are many more of them. Consider the political calculus. On the left, reformers want to subsidize alternatives to marriage. In the middle, unmarried straights like the idea of new benefits (why not?). Gay groups figure the surest way to get and keep partner programs is to give the straight majority a stake in them. The right’s main concern is blocking marriage for homosexuals.

No surprise, then, to learn that most partner programs in America are in fact open to both same-sex and opposite-sex couples–about two-thirds of them, according to the Human Rights Campaign, which keeps tabs on public and private programs. As of the end of 2002, nine states, the District of Columbia, and 140 municipalities and other local government agencies offered domestic-partner benefits (including at least health insurance); 70 percent of those programs were open to both gay and straight couples. Among the Fortune 500 companies, 154 offered domestic-partner programs, of which just over 60 percent were open to straight couples. The Human Rights Campaign finds that the number of employers providing domestic-partner health benefits has been growing by roughly 20 percent a year since 1999, and about two-thirds of the programs are straight-inclusive.

Moreover, political pressures being what they are, some jurisdictions have passed “equal benefits ordinances” requiring that partner programs be “nondiscriminatory” (that is, open to heterosexual couples), and court and administrative rulings tug in the same direction. In 1996, the city of Oakland, Calif., set up a gays-only partnership program for city workers. The city tried to hold the line, but it was finally forced to admit unmarried heterosexuals when the state labor commissioner ruled that excluding them constituted illegal discrimination. In Santa Barbara, the city attorney likewise opined that gays-only benefits were illegal, and the city extended its program to include opposite-sex unmarried couples.

As partner programs multiply and lose their exotic air, more heterosexuals will sign up for them. According to the Human Rights Campaign, the number of people on the health-benefits roster grows by 1 percent when partner benefits are granted only to gay couples but by 3 percent when the benefits are opened to straight couples–suggesting that roughly two-thirds of the participants are heterosexual. That should not be surprising. There are many more straights than gays. So what we are talking about is not a hypothetical slippery slope toward heterosexual marriage-lite. The slide is already under way, here and now.

In response, conservatives might say, “You’re right! There is only one solution. Stop the partner programs. The way to protect marriage has got to be: no same-sex marriage, no domestic-partner programs, no nothing. Gays will just have to cope on their own.” No good. Worse, in fact.

Domestic-partner programs are not the only competitor to marriage, nor are they even the most important. More common and more destabilizing–and open to gays and straights alike–is cohabitation. If gay couples are denied both legal marriage and domestic partnership, they will just live together outside of marriage, as many are now, but rightly enjoying even more social recognition. They will come to the office holiday party together and house-shop together and entertain together and, perhaps, raise children together, all of which will bolster the status of cohabitation as a respectable, and in many ways equivalent, alternative to marriage. Over time, as society makes room for unmarried but devoted same-sex couples, custom and law will start providing cohabitants with many of marriage’s benefits–only without the bother of formal commitment, legal responsibilities, or a messy divorce. Many heterosexual couples, including many with children, will be only too happy to take that deal. Just such a trend is already well along in Canada and a number of European countries, where the legal and social boundaries between cohabitation and marriage are quickly blurring.

The trend toward social recognition of same-sex couples is past stopping. The pending question today is whether to bestow society’s blessings on marriage or on something else–marriage-lite or socially approved cohabitation or, most likely, both. Already, in America, if you want to get together with someone, and depending on where you live or work, you can have cohabitation, employer domestic-partner benefits, public domestic-partner benefits, marriage, or even covenant marriage (a version of marriage which is harder to get into and out of). At this rate, marriage may become merely an item on a mix-and-match menu of lifestyle options, a truffle in the candy box. It might even become the preserve of the old-fashioned. “Oh, you’re getting a traditional marriage? Isn’t that charming!”

Marriage is durable and, one way or another, will survive, even in a world of proliferating alternatives. What seems incontestable, however, is that empowering a bunch of competitors cannot do marriage any good, especially if the competitors offer most of the benefits with fewer of the burdens. If marriage’s self-styled defenders continue along the path toward making wedlock just one of many “partnership choices” (and not necessarily the most attractive), they will look back one day and wonder what they could possibly have been thinking when they undermined marriage in order to save it from homosexuals.

Jonathan Rauch is a writer in residence at the Brookings Institution. This article is drawn from his book, Gay Marriage: Why It Is Good for Gays, Good for Straights, and Good for America, published in April 2004 by Times Books, an imprint of Henry Holt and Company.

Jonathan Rauch is a writer in residence at the Brookings Institution. This article is drawn from his book, Gay Marriage: Why It Is Good for Gays, Good for Straights, and Good for America, published in April 2004 by Times Books, an imprint of Henry Holt and Company.

Jonathan Rauch

Jonathan Rauch is a senior fellow at the Brookings Institution.