You're probably familiar with the conservative case for gay marriage, articulated most eloquently by Andrew Sullivan on many occasions. Here is one:
Conservatives have long rightly argued for the vital importance of the institution of marriage for fostering responsibility, commitment and the domestication of unruly men. Bringing gay men and women into this institution will surely change the gay subculture in subtle but profoundly conservative ways. When I grew up and realized I was gay, I had no concept of what my own future could be like. Like most other homosexuals, I grew up in a heterosexual family and tried to imagine how I too could one day be a full part of the family I loved. But I figured then that I had no such future. I could never have a marriage, never have a family, never be a full and equal part of the weddings and relationships and holidays that give families structure and meaning. When I looked forward, I saw nothing but emptiness and loneliness. No wonder it was hard to connect sex with love and commitment. No wonder it was hard to feel at home in what was, in fact, my home.
For today's generation of gay kids, all that changes. From the beginning, they will be able to see their future as part of family life — not in conflict with it. Their "coming out" will also allow them a "coming home." And as they date in adolescence and early adulthood, there will be some future anchor in their mind-set, some ultimate structure with which to give their relationships stability and social support. Many heterosexuals, I suspect, simply don't realize how big a deal this is. They have never doubted that one day they could marry the person they love. So they find it hard to conceive how deep a psychic and social wound the exclusion from marriage and family can be.
Gay marriage ought to be legal. Most conservatives and libertarians I know who are 30 or younger feel the same way, even if we'd rather that judges not impose it. (The established rules of our state constitutions protect so many rights under a strict constructionist reading. Loose constructionists, though most seek to guarantee more liberty, risk undermining the liberty we already possess by permitting interpretations that haven't any grounding in the text.)
There are non-bigoted arguments against gay marriage -- basically the view that any change to a vitally important, long held institution should be resisted. But I never quite grasp why some conservatives find the notion of gay people getting married a bigger threat to traditional family norms than the alternative -- that is, gay people who aren't married living together and having sex, raising children, etc., within a gay culture where monogamy is a less powerful norm.
Isn't that a more transgressive lifestyle, by the lights of conservatism, than gay people being married? And isn't it obvious that is the choice that society faces? Andrew wrote about the conservative norms gay marriage would communicate to young homosexuals. I'd add that the same goes for young straight people!
If you're a conservative who opposes gay marriage, do me the favor of considering a hypothetical, which I've long sought a response to:
An 8-year-old goes to play at the house of his friend, who is raised by two lesbian women. The environment is a loving one. So this playmate, whose straight parents are married, is going to absorb one of two possible norms.
1) My friend lives in a happy home. His parents are married. When people grow up and love each other, and want to have kids and a happy home, they get married. (I hope I get married one day.)
2) My friend lives in a happy home. His parents aren't married. When people grow up and love each other, and want to have kids and a happy home, sometimes they get married like my parents. Other times they don't get married, like my friend's parents. (One day I may get married and have kids, but maybe I'll just have kids and live with the person I love.)
Conservatives should prefer the former scenario.
Yet many advocate gay marriage bans that bring about the latter scenario -- not just when kids happen to meet gay parents in elementary school, but when they see gay people in television shows or movies, start having dinner at a gay professor's house in college, or converse with gay friends they meet in their twenties.
These gay people, if they cannot marry, are going to cohabitate and have kids anyway. Why undermine the norm of married family life by denying them the ability to practice it? Why create a whole category of people to spread the norm of unmarried family life?