Not long ago, hundreds of progressive academics and activists issued a manifesto calling for health care and jobs for all, universal peace, an end to hunger, and the equal recognition of all relations among sentient creatures. Robert George, a prominent natural-law professor at Princeton who opposes gay marriage, took this rather stale document as fresh proof that gay marriage will lead to polygamy.
George understands the radical argument for gay marriage. It claims, as he notes, that "love makes a family" and that making any legal distinctions among people who love each other is unjustified. George concludes that this love-makes-a-family ideology "is central to any principled argument" for same-sex marriage.
That's wrong. While George understands the most open-ended argument for gay marriage, it does not appear that he has taken the time to understand more careful, restrained, and conservative arguments for gay marriage, like those advanced by Jonathan Rauch, Andrew Sullivan, me, and others. I won't repeat the substance of these arguments here, but suffice it to say they do not easily lend themselves to support for polygamy; they certainly involve more than saying simply, "love makes a family."
George complains that we have not made what he calls "principled" arguments about why the recognition of same-sex marriages does not entail the recognition of polygamous ones. Instead, we have made what he calls "pragmatic" and "prudential" arguments, emphasizing differences between SSM and polygamy in terms of their respective histories, expected effects on society and marriage, and predicted benefits to the people involved.
When you read modern natural-law writings about marriage, you find that by "principle" something like this is meant: "Marriage must be between a man and a woman because only they can procreate; as for sterile male-female couples, they are included because they can have sex of a reproductive kind." Sex "of a reproductive kind" is sex that involves a penis and a vagina, even if it can produce no more babies than could a male and a male or a female and a female. The conclusion of the argument is embedded in the "principle" and then offered as if it's an argument.
In his scholarship, George has asserted that male-female marriage, and only male-female marriage, has an "intrinsic value" that "cannot, strictly speaking, be demonstrated." Its value "must be grasped in noninferential acts of understanding." This "noninferential understanding" that "cannot be demonstrated" is unavailable to some people, argue modern natural-law theorists. Another natural-law writer, Professor Gerard V. Bradley, adds that, "In the end, one either understands that spousal genital intercourse has a special significance as instantiating a basic, non-instrumental value, or something blocks that understanding and one does not perceive correctly."
This amounts to saying: "Same-sex 'marriage' is not marriage because only male-female marriage can be marriage. Trust me." The modern natural-law argument against same-sex marriage at bottom thus appears to rest on revelation of some pre-cognition reality to the initiate and only to the initiate. This seems to me very close to saying that marriage just is the union of one man and one woman and cannot, no matter the arguments, be defined any other way.
But advocates of a logical slide to polygamy need to show the necessary "principle" uniting the causes of same-sex marriage and other unions, like polygamous ones. Yes, you can imagine such a principle ("love makes a family") and even find support for it in slogans and in the writings of some academics and activists who say they favor gay marriage but also favor many other reforms. The manifesto that has George so excited actually says very little about polygamy, but prominently calls for an end to "militarism," and repeatedly for a wide range of government social-welfare measures. Must gay-marriage advocates who didn't sign the manifesto produce position papers and principles against state-controlled universal health care, too? Same-sex marriage is no more necessarily tied to polygamy than it is to all of these other proposals.
And when it comes to crafting public policy, why don't pragmatic and prudential considerations count as serious arguments? If same-sex marriage will benefit the individuals involved, any children they're raising, and their communities, all without plausibly harming marriage, does this not matter as against a claim that a conclusory principle stands in the way?
If polygamous/polyamorous marriage raises a host of different questions about harm, practical administration, and about historical experience, none of which depend necessarily on how we've resolved the debate about gay marriage, why must gay-marriage advocates definitively address it?
The way we frame the debate about gay marriage matters not just for the ultimate outcome, but for the shape and attributes of that outcome. Those of us who have been making a conservative case for gay marriage do so, fundamentally, because we believe in marriage. We do not want to see it harmed and we do not think that this reform means every proposed reform of marriage, including potentially harmful ones, must be accepted.
Ironically, George and the manifesto-signers agree that gay marriage means anything goes. I don't expect that George and other conservative opponents of gay marriage will hold to that position when gay marriage is actually recognized (indeed, they'll strongly resist the supposed slippery slope to polygamy then), but the damage they are doing now by making a tactical alliance with marriage radicals and arguing the line cannot be held will not have been helpful.