Abstract

Opponents of same-sex marriage suggest that legalizing same-sex marriage will start a slide down the "slippery-slope" leading to the legalization of all kinds of salacious family arrangements including polygamy. In this paper, I argue that because previous attempts by liberal political theorists to combat such slippery-slope arguments have been unsuccessful, there are two options left open to political liberals. Either one could embrace polygamy as a logically consistent implication of extending civil liberties to same-sex couples or one could find a new strategy for blocking the slide down the slope. I take the second option arguing that we ought to devise a harm principle for domestic partnerships. Once this principle has been established, it becomes clear that the risk of exploitation for those potentially occupying the multiple side of the marriage is sufficient reason to reject polygamous marriage arrangements. I conclude that, contrary to appearances, holding both (a) same-sex marriage is permissible and (b) polygamous marriage is impermissible is at the same time consistent and consistently liberal.