So some of you may be worried that the Salt Lake City air is getting to me. But this is something that I've thought about for a while now and only finally getting around to putting into pixels. One of the presenters at the NEH basically made the same point in passing today, which reminded me that I'd never posted on it.
Here's my claim: the arguments for the legitimacy (whether we're thinking legal or moral here, I don't think that it matters) same-sex marriage can also be used to establish the legitimacy of polygamy. Now, I'm not making a claim about either the strength of the arguments here or the truth of their conclusions; I'm making only a claim about the relationship between two kinds of arguments.
Take any plausible argument for same-sex marriage; for instance, consider the general argumentative strategy that marriage is a civil or legal relationship or contract that consenting adults enter into. Then simply take that argument and change it from being about qualities of those entering into the relationship to being about the quantity of those entering into the relationship. If the 'parts' don't matter for such a relationship or contract, I cannot see why the number of consenting adults would matter. If there is no relevant different between same-sex marriage and polygamy on the basis of social contract or agreement, then arguments for the former can also be used as arguments for the latter. Sure, there are ways that one could block the move from same-sex marriage to polygamy, but I can't think of any reason why these wouldn't be rather ad hoc and superficial.
I think you are certainly correct, at least if you restrict arguments for SSM to rights-based arguments. Ralph Wedgewood, for example, in his 1999 paper defending SSM basically argues that we should allow SSM because a lot of people want it, it doesn't intrude on anyone's liberty, and it didn't undercut the symbolic function of marriage. He considered whether this established a right to polygamy, but concluded that it did not, because not enough people wanted to engage in polygamous relationships. I didn't find that persuasive.
The advocate of SSM can avoid this conclusion if he takes a different approach to justifying SSM. For instance, there is the conservative case for SSM: according to this case, we should allow SSM because instituting marriage won't damage the institution of marriage and will have positive effects for the gay community--there will be less promiscuity, for example. (This is how Jonathan Rauch argues in his 2004 Gay Marriage, and I believe this is how Dale Carpenter, and, to some extent, Andrew Sullivan argue as well.) Notice that the conservative SSM advocate isn't committed to these same claims regarding polygamy: for all he knows polygamy will overall harm the participants, in general.
Nevertheless, this is unattractive to most proponents of SSM because it seems to make the case for SSM a consequentialist, rather than a rights-based, one. So, I think most proponents of SSM are committed to supporting polygamy, even if it has really bad consequences.
Kevin, I think you're correct, though I think this argument has been made a number of times in conservative circles.
Rob, the problem with the conservative argument is that there isn't any evidence to suggest that gay marriage will lead to less promiscuity. While there is a strong assumption in favor of monogamy in heterosexual marriage, the same assumption doesn't hold in the case of gay marriage.
Me, make a consequentialist-based argument? As if.... :)
Well, I never claimed to be original.
Hi Matthew,
There might not be any evidence, but Rauch would respond that that's because gay men have grown up thinking of marriage as something off-limits to them, and so have come to think of sexuality in different ways from the way straights think of it. There's also, of course, the male-male sex-drive, which, if real, makes monogamy more difficult to achieve in the case of gay men than it is for straights or lesbians. But as for the lack of evidence, Rauch would counsel: just wait.
Extending marriage to multiples greater than 2 would be more complicated than extending it to same-sex couples. Currently, virtually all of the institutions regarding marriage work just as well regardless of sex, but they do often make the assumption that there are 2 people. Examples of unresolved policy vaccums:
-do all parties need to agree to marry each other?
-should insurance rating and similar concerns include all spouses?
-does a divorce need to be between all parties?
-how to split things in a divorce?
-do tax benefits etc. increase/decrease with number of people in the marriage?
-child custody issues
Clearly not a simple transition