Is there any logic in opposing gay marriage?

There is a great piece by Jonathan Chait in TNR, called Until Logic Did Them Apart about the anti gay marriage argument.

Chait begins with the observation the argument against gay marriage is most often expressed as "I believe marriage should be between a man and a woman".

The anti-gay-marriage soundbite.... makes no attempt at persuasion. .... You believe that marriage should be between a man and a woman? Okay! But why?

And then the truth comes out. This argument relies on the idea that gay marriage takes away from the opponents' right to define marriage....basically, their right to discriminate.

....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 anti-gay marriage] 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.

Then there is the procreation argument.

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...

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Because, of course, we do not deny gay marriage to the old, the infertile, or the sterile. Chait ignores the counter argument that many gay families have children, so if anything this is discriminatory AGAINST families. I discussed with the children issue here.

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."

Right. SO gays can marry, so why would straight guys want to marry ? Is this any sort of argument? Chait also finds it insupportable.

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 openly discriminate like this, but most people aren't, which is why public opinion is warming to gay marriage. Most opposition arises from simple discomfort.....

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.

Go read the whole thing!