Yet for an argument that has persuaded so few, the conservative view has actually had decent predictive power. As the cause of gay marriage has pressed forward, the social link between marriage and childbearing has indeed weakened faster than before. As the public’s shift on the issue has accelerated, so has marriage’s overall decline. 

Since Frum warned that gay marriage could advance only at traditional wedlock’s expense, the marriage rate has been falling faster, the out-of-wedlock birthrate has been rising faster, and the substitution of cohabitation for marriage has markedly increased. Underlying these trends is a steady shift in values: Americans are less likely to see children as important to marriage and less likely to see marriage as important to childbearing (the generation gap on gay marriage shows up on unwed parenting as well) than even in the very recent past. 

Correlations do not, of course, establish causation. The economy is obviously playing a leading role in the retreat from marriage — the shocks of recession, the stagnation of wages, the bleak prospects of blue-collar men. Culturally, what matters most is the emergence of what the National Marriage Project calls a “capstone” understanding of marriage, which treats wedlock less as a foundation for adulthood and more as a celebration of adult achievement — and which seems to work out far better for our disciplined upper class than for society as a whole. 

But there is also a certain willed naïveté to the idea that the advance of gay marriage is unrelated to any other marital trend. For 10 years, America’s only major public debate about marriage and family has featured one side — judges and journalists, celebrities and now finally politicians — pressing the case that modern marriage has nothing to do with the way human beings reproduce themselves, that the procreative understanding of the institution was founded entirely on prejudice, and that the shift away from a male-female marital ideal is analogous to the end of segregation. 

Now that this argument seems on its way to victory, is it really plausible that it has changed how Americans view gay relationships while leaving all other ideas about matrimony untouched? 

You can tell this naïveté is willed because it’s selective. There are plenty of interesting arguments, often from gay writers, about how the march to gay marriage might be influencing heterosexual norms — from Alex Ross’s recent musings in The New Yorker on the sudden “queer vibe” in straight pop culture to Dan Savage’s famous argument that straights might do well to imitate the “monogamish” norms of some gay male couples. It’s only the claim that this influence might not always be positive that is dismissed as bigotry and unreason. 

A more honest, less triumphalist case for gay marriage would be willing to concede that, yes, there might be some social costs to redefining marriage. It would simply argue that those costs are too diffuse and hard to quantify to outweigh the immediate benefits of recognizing gay couples’ love and commitment. 

Such honesty would make social liberals more magnanimous in what looks increasingly like victory, and less likely to hound and harass religious institutions that still want to elevate and defend the older marital ideal.

But whether people think they’re on the side of God or of History, magnanimity has rarely been a feature of the culture war. [Marriage Looks Different Now, NYT, March 30, 2013]

Back in 2000, I wrote in National Review:

But could it be, instead, that fewer gay men want to be married than to get married? Does gay marriage appeal more because sexual fidelity offers a role for a lifetime, or because a wedding provides the role of a lifetime? ... 

So legalizing single-sex marriage isn't likely to prevent the next gay venereal epidemic. Yet, will gay weddings destroy society? Overall, I'm not terribly worried. Still, the fervor with which some gay grooms will pursue the perfect wedding will make straight men even less enthusiastic about enduring their own weddings. The opportunities for gays to turn weddings into high-camp farces are endless. For example, if two drag queens get married, who gets to wear white? And anything that discourages straight men from marrying would be widely harmful. While most straight guys eventually decide that being married is fine, the vast majority find getting married a baffling and punitive process. (You may have noticed that while Modern Bride magazine is now over 1,000 pages long, there is no Eager Groom magazine.) About the only comment a straight man can make in favor of his role is that at least it's a guy thing … not a gay thing. But for how much longer?

My experience with being married has been that it’s great. On the other hand, my experience with getting married (e.g., worrying about the color of tablecloths, registering for domestic gifts that I never wanted and couldn’t imagine using, etc.) was that it was a nightmare than any self-respecting masculine man would only put up with for love. From a self-respect standpoint, about all you could say for being a groom was that it was, legally, a guy thing, not a gay thing.

Now, the gays are trying to make getting married de jure into even more of a gay thing than it already tends to be de facto.

Those of us on the right half of the bell curve ought to ask ourselves what guys on the left half of the bell curve are going to think as gays increasingly become the most theatrical participants in getting married? Is this really going to be good for society on the whole?

I'm not predicting that many guys will articulate this feeling, but that's who we need to worry about: the less articulate.

Of course, the notion that gay marriage most disturbs men with two-digit IQs is widely seen as a feature, not a bug. A boot stamping on the human face of a social inferior forever is nirvana.