As anyone following debates over redefining marriage to include same-sex unions can see, such a redefinition would not be the final step in how marriage changes. And I'm not talking about how the norms that are associated with traditional marriage might change. Reading through Judge Vaughn Walker's ruling against California's Proposition 8, he states that gender is unimportant in marriage any more. Or, to be precise, that "gender no longer forms an essential part of marriage."
Such a claim may or may not sound radical to you, but he makes the case that in the eyes of the state, the gender composition of marriage is of no interest at all whatsoever.
If something as key to marriage as gender complementarity is unessential to marriage, certainly the number of participants is just as unimportant. The number limitation really hinges on the gender complementarity issue. If it's not about two humans who, through the conjugal act, unite in one flesh, than why can't a loving committed family be formed from three or more people (of whichever gender you prefer)? What's important, in the post Lawrence age, is that society allow its citizens to autonomously construct their own concept of existence as it relates to their love lives, no?
Over at Public Discourse, Christopher Kaczor, Professor of Philosophy at Loyola Marymount University, argues that recent empirical research suggests that polygamy is socially detrimental--to society in general, to men, to women, and to children. But he ends on a non-empirical note:
Finally, even aside from the sociological data, there is an inherent inequality in polygamous marriage. In monogamous marriage, spouses give themselves as spouses to each other unreservedly, unconditionally, and entirely. Now, giving oneself as a husband or wife to one’s spouse does not exclude giving of oneself in ways that are not distinctly marital to other people (such as playing tennis with a business partner, or going to the movies with a group of friends). Part of the marriage vow is the promise of sexual fidelity, the bodily manifestation of one’s commitment as spouse entirely to the spouse and to the spouse alone.
In a polygamous marriage, the man does not give himself qua husband entirely to his wife. A polygamous husband gives himself qua husband to however many wives he has. Wives, by contrast, are expected to reserve themselves in a sexual way for their husband alone. Moreover, wives face inequality among themselves as “senior wives” enjoy rank above “junior wives.” The polygamous relationship can never attain the mutual and complete self-donation of spouses in monogamous marriage because it is intrinsically impossible to reserve oneself in a sexual way entirely for one person and at the same time reserve oneself in a sexual way entirely for a different person (or persons). Marriage understood as a comprehensive union can exist only between two persons, and never more than two persons. Society, therefore, has good reason not simply to proscribe polygamy, but to endorse monogamy.
To be honest, while I agree with what Kaczor identifies here as a problem with polygamy, to use the same reasoning that is applied in same-sex marriage redefinition cases, the judge might say that since the law doesn't require one spouse to give entirely to the other spouse already, it is nothing more than harmful bigotry to deny marriage equality to multiple adult arrangements. It's definitely religious bigotry considering that Islam permits a man to take multiple wives.
The fact is that polygamy, unlike same-sex marriage, actually has been a part of marriage culture. It is a part of marriage culture in various parts of the world right now. If we're honest, without Jesus' words in favor of one-man, one-woman arrangements, it would probably be more widespread. And I'm sure Newsweek can come up with a "Jesus' Case For Polygamy" cover soon, if they haven't already.
Can anyone think of any principle for limiting marriage to two people now that we're discarding the old bigoted definition of marriage in favor of a new and more ambiguous one?