SSM: MY BASIC POSITION. This is long but I think it’s pretty plain-spoken:

Americans still think the debate over same-sex marriage is about gay people. We still think it’s about your best friend who’s just said she’s a lesbian, or your son who’s just come out. We still think it’s about whether homosexual acts are sinful.

It’s not.

The same-sex marriage debate is about marriage, above all else. It’s about a view of marriage that was first promoted by and for heterosexual couples.

I used to dream about same-sex marriage. In high school I was in love with a girl who was the marryin’ type. I used to think about the future, when we’d be married. We joked about how my parents would be her in-laws.

So I think I have some grasp on why gay-rights activists are pushing for marriage. Homosexual couples love one another dearly, and they want recognition of this love. They want to feel like society honors their emotional commitments. They envision marriage as a kind of Good Housekeeping Seal of Approval.

But there are all kinds of intense relationships that society does not honor the way it honors marriage. There are best friends (which many women will recognize as the closest relationship they’ve ever had); mentors; grandmothers; beloved teachers.

Why do we give marriage more societal honor than we give these other, often deeply important, relationships? Because we recognize that marriage has evolved to do more than these other relationships do for society. These relationships do less (not nothing, just less) to nurture children; to bind the young to the old; to corral the often destructive forces of desire into productive and loving channels; to bring people from youth to adulthood; and to align the interests of parents and children, rather than forcing tragic choices between the two. Marriage gets “props” from society because it does all these things more than any other institution does, or could.

Marriage developed over centuries to meet several specific, fundamental needs: children’s need for a father. A couple’s need for a promise of fidelity (and consequences for breaking that promise). Young people’s need for a transition to manhood or womanhood. And men’s (and women’s, but mostly men’s) need for a fruitful rather than destructive channel for sexual desire–a way of uniting eros and responsibility. In other words, marriage developed to meet the needs of opposite-sex couples. Why would same-sex couples expect that this institution would meet their very different needs?

At best, marriage only addresses one need of homosexual couples: sexual fidelity. Even there, it should be obvious that same-sex couples will be less likely to insist on physical fidelity than heterosexual couples. If your man might make babies with someone else, you’re more likely to see the point of restrictions on male sexuality. If you can get pregnant, you’re more likely to see the problems that might result if the father isn’t legally tied to you. So the connection between sexual fidelity and the institution of marriage is a basic consequence of the fact that when men and women–but not same-sex couples–have sex, babies often result. When the institution is no longer responding to opposite-sex couples’ needs, we can expect the emphasis on sexual fidelity to weaken.

Canada has already legalized same-sex marriage. A case now trudging through the Massachusetts courts could ultimately do the same for this country. It may seem like we’re stepping into an unknown world.

But it’s not so new. Same-sex marriage is the next step in the long process of thinning and weakening marriage. Marriage is narrowed from a complex institution serving a variety of needs–focused on the needs of children–to a contractual arrangement between two adults to validate their romantic desires. In this “thin” notion of marriage, children are not the greatest fruit of marriage, the preeminent sign of a couple’s union; they are at best optional extras.

For several decades now, we’ve been watching the unfolding consequences of the “thin,” individualist concept of marriage. Those consequences include broken families and fatherless children. Heterosexual couples have begun to reject this model of marriage–the divorce tide is ebbing, and most Americans now realize that children do best when they’re raised by their married parents.

Same-sex marriage would revive the mistaken view of marriage that spurred the rise of divorce and family fragmentation–and more than merely reviving this mistaken idea, would enshrine it in law. While the heterosexual world is waking up to the problems caused by the adults-first, individualist version of marriage, same-sex couples are pushing for that vision to become the law of the land.

Same-sex marriage is about marriage.