Beauty pageant contestant Carrie Prejean, asked about gay marriage a few weeks ago, summed up her view this way: "In my country and in my family, I think that I believe that marriage should be between a man and a woman." It's a pretty simple answer—what you'd expect, intellectually, from someone who had just successfully completed a bikini walk rather than a dissertation on the topic at hand.
Around the same time, Rudy Giuliani framed his own thinking in similar terms: "Marriage, I believe, both traditionally and legally, has always been between a man and a woman and should remain between a man and woman." (In Giuliani's case, he means a man and one woman at a time, though some romantic overlap may be unavoidable.)
Gay-marriage opponents have made that formulation their mantra. It's a really strange way for them to summarize their argument, because it's not an argument at all. If we're debating health care, one side will have a line about big government, and the other will have a line about the uninsured or spiraling costs. If we're debating torture, advocates will mention the need to make terrorists talk, and opponents will invoke American values. Soundbites, by their nature, can't express much logical nuance, but they do tend to give you a reason to agree with the position.
The anti-gay-marriage soundbite, by contrast, makes no attempt at persuasion. It's like saying you oppose the Bush tax cuts because "I believe the top tax rate should be 39.6 percent." You believe that marriage should be between a man and a woman? OK! But why?
The ubiquity of this hollow formulation tells us something about the state of anti-gay-marriage thought. It's a body of opinion held largely by people who either don't know why they oppose gay marriage or don't feel comfortable explicating their case.
In a liberal society, consenting adults are presumed to be able to do as they like, and it is incumbent upon opponents of any such freedom to demonstrate some wider harm. The National Organization for Marriage, on its website, instructs its activists to answer the who-gets-harmed query like so: "Who gets harmed? The people of this state who lose our right to define marriage as the union of husband and wife, that's who." Former GOP Senator Rick Santorum, arguing along similar lines, has said, "[I]f anybody can get married for any reason, then it loses its special place."
Both of these arguments rest upon simple tautologies. Expanding a right to a new group deprives the rest of us of our right to deny that right to others. If making a right less exclusive devalues it, then any extension of rights is an imposition upon those who were not previously excluded—i.e., women's suffrage makes voting less special for men.
Another objection holds that gay marriage would weaken the link between marriage and child-rearing, therefore encouraging out-of-wedlock births. If true, this would at least provide some weight on the scale against gay marriage. But it suffers from two massive flaws. First, it's hard to imagine how the tiny gay minority's behavior can materially influence the way the vast majority of heterosexuals view marriage. Second, if you think about it, the causality gay-marriage opponents imagine is running the wrong way. Suppose we had a social epidemic of young adults who moved back into their parents' houses and watched television all day rather than finding a job. You might want to strengthen the link between adulthood and work. You'd be concerned about anything that weakened this link by letting adults not work--say, early retirement. But you wouldn't be concerned about the social signals sent by teenagers finding summer jobs. That would be weakening the link between adulthood and work, but not in the harmful way.
Likewise, marriage proponents might worry about anything that expands childbearing to the non-married, but they have no reason to fear expanding marriage to the non-childbearing. This is why approximately zero people in the history of the human race have ever expressed concern about allowing old or otherwise infertile heterosexuals to marry, even though they account for a far larger percentage of marriages than gays ever could.
The most striking thing about anti-gay-marriage arguments is that they dwell exclusively on how heterosexuals would be affected. Heather Mac Donald of the conservative Manhattan Institute writes, "I fear that it will be harder than usual to persuade black men of the obligation to marry the mother of their children if the inevitable media saturation coverage associates marriage with homosexuals."
I suppose you could imagine, somewhere, a black man telling his friends he's going to propose to his pregnant girlfriend, only to be taunted, "Marriage? That's so gay," and think better of it. I don't find this very likely. Neither does Mac Donald, actually. "[I]f someone can persuade me that the chances are zero, then I would be much more sanguine," she writes. "But anything more than zero, I am reluctant to risk."
This is the One Percent Doctrine of social policy. If you place zero weight upon the preferences of gays, then all you have to do is suggest a possible harm, however remote, associated with gay marriage. The same sensibility was on stark display in a recent National Review editorial. Dismissing the argument that marriage might foster more stable gay relationships, the magazine's editors replied curtly, "[T]hese do not strike us as important governmental goals." There's a word for social policy that disregards the welfare of one class of citizens: discrimination.
Some hard-core conservatives are willing to discriminate openly like this, but most people aren't, which is why public opinion is warming to gay marriage. Most opposition arises from simple discomfort. When I first started hearing about gay marriage. I didn't oppose it, but it seemed sort of strange and radical—and only after several years did I realize I supported it.
The line "I believe that marriage should be between a man and a woman" is an expression of that sensibility—a reflection of unease rather than principle. As people face up to the fact that opposing gay marriage means disregarding the happiness of the people most directly (or even solely) affected by it, most of us come around. Good ideas don't always defeat bad ideas, but they usually, over time, defeat non-ideas.
Jonathan Chait is a senior editor at The New Republic.