Civil unions: the radical choice.

All the leading Democratic candidate--including Howard Dean--have come out against same-sex marriage, supporting civil unions as a moderate alternative. The great irony is that civil unions aren't actually a moderate choice. On the contrary, they have far more radical implications than gay marriage.

Consider France, which allows gay people to apply for something called a civil solidarity pact. Because this option isn't limited to same-sex couples, it has caught on like wildfire, and as many as half of those who register are straight. (One reason? The pact can be dissolved by either party on three months' notice.) Other European nations have embraced similar arrangements in recognition that many heterosexuals prefer a less binding commitment than marriage. That's true in the United States as well. According to sociologist Andrew Hacker, a third of U.S. women are unmarried at the age of 30. This figure would have astonished our ancestors, but it won't raise the roof on Oprah.

Call it the libertarian approach to family: You follow your heart and let the changes come as they may. Civil unions reflect this climate of choice and flexibility. Ultimately they have less to do with gay fights than with giving all couples a way to codify their relationships--and protect their children--without taking on the full weight of matrimony. Millions of straight couples would take advantage of this alternative ff they could. Rest assured that once civil unions become commonplace, hets will demand to be included--and they ought to be.

Rick Santorum's obsession with polygamy and incest is beside the point. These practices are far too unpopular to push their way under the marriage umbrella. But what about the many seniors who live together and don't want to betray the memory of a dead spouse? How can you say no to a retired couple? It's a question the New Jersey legislature is grappling with as it considers a domestic-partnership law that includes not just gay people but "also the elderly. Such statutes point to a future in which couples will have many options, from "covenant marriage," in which both parties sign a contract pledging not to divorce, to a number of less binding choices.

Civil unions won't replace marriage, but they could make it rarer. Same-sex marriage has no such potential. It won't expand the matrimonial options, and courts are unlikely to apply the principle of equal protection to straight couples who don't want to wed even though they can. In fact, there's a real possibility that employers will cancel domestic-partner benefits once gays can marry. If that happens, all couples will be faced with the same rigid choice: Tic the knot, or you're on your own.

My fellow and suroral leftists are right to regard gay marriage as a conservative idea. It would bolster an institution that can be very encumbering and that deprives single people of the government benefits they deserve. The solution to this problem is not to oppose same-sex marriage rights but to demand universal health care and flexible pensions. We can wage that fight even as we struggle for equality. That's why progressives should support marriage, civil unions, and any other arrangement that allows couples to share their affection without restricting their entitlements.

As the Supreme Court noted in its ruling overturning sodomy laws, every generation must be allowed to discover for itself what freedom means. That certainly applies to intimacy, which is a journey with many destinations. The state ought to empower people to make commitments pretty much as they see fit. Different strokes for different folks! That's not just the premise of gay liberation; it's the American way.