On Slate, Jillian Keenan argues, “We need to legalize polygamy, too”:
Legalized polygamy in the United States is the constitutional, feminist, and sex-positive choice. More importantly, it would actually help protect, empower, and strengthen women, children, and families.…
The definition of marriage is plastic. Just like heterosexual marriage is no better or worse than homosexual marriage, marriage between two consenting adults is not inherently more or less “correct” than marriage among three (or four, or six) consenting adults. Though polygamists are a minority—a tiny minority, in fact—freedom has no value unless it extends to even the smallest and most marginalized groups among us.
From those who make arguments in favor of a constitutional right to same-sex marriage, I’ve never heard a convincing explanation why those arguments wouldn’t also compel recognition of a constitutional right to polyamory. (See, for example, Ted Olson’s feeble answer to Justice Sotomayor’s question at oral argument.) Yes, of course, there would be some administrative complications in, say, prorating spousal benefits. But for those who regard polyamory as essential to their happiness, those minor complications could hardly justify denying what the Prop 8 plaintiffs vaporously describe as “a right … that is central for all individuals’ liberty, privacy, spirituality, personal autonomy, sexuality, and dignity; a matter fundamental to one’s place in society; and an expression of love, emotional support, public commitment, and social status” (emphasis in original).
The only minor flaw that I see in the “slippery slope” argument is that polyamory may well be upslope of same-sex marriage. By contrast to the novelty of same-sex marriage, polyamory—or at least its polygamous version (one husband, more than one wife)—has a long history. Within the broader tradition of marriage, insisting on the difference between two and three (or two and seven) is surely more arbitrary than recognizing the difference between a male-female union and a same-sex union.