Waychel: You seem to be saying that (1) marriage laws are specifically designed to maintain traditional gender roles in our society, (2) this is a good thing, (3) and allowing same-gender marriages would undermine this.
The first is a matter of fact: you are wrong.
The second is a matter of opinion: I disagree.
The third is moot, though maybe hypothetically correct.
As for the slippery slope, I think you're being really naive. There has already been
one major expansion of marriage based on "equality," and that didn't lead to legalized polygamy.
99% of proponents of gay marriage are like me: We think that marriage should remain an exclusive commitment by two consenting adults to share their lives. We don't think that these two people should be limited by their race, gender, religion, political affiliation, or hair color.
Redefinitions of marriage have come from widespread political pressure. There is now pressure to redefine the gender requirements. Maybe in the future there will be pressure to redefine the number of participants, but there is nothing even approaching that now.
When there is a single pro-polygamy ruling in the US courts citing same-sex marriage as a precedent, then this will be a legitimate argument. Not until then.
Kobun Heat: I'm not sure what the libertarian perspective on marriage would be, but I'll hazard a guess. Libertarians don't like it when the government limits the kinds of contracts you can make, but they do think the contracts should be enforced (though some would prefer a private, for-profit justice/security system).
Marriage is a contract, and most people who enter into it don't bother hammering out all the details beforehand in a prenup. So it would make sense for the government to determine what was implied in a marriage contract, and enforce that in cases where the couple didn't draw up a different set of rules.
Loki: I'll put my career on hold if you want, but the kids are getting bar mitzvahs.
