The Progressive favors extending the legal institution of marriage so as to include same-sex unions along with heterosexual ones. The Traditionalist opposes such an extension, preferring to retain the legal institution of marriage in its present form. I argue that the Progressive ought to broaden her position, endorsing instead the Liberal case for extending the current institution so as to include polygamous unions as well—for any consideration favoring Progressivism over Traditionalism likewise favors Liberalism over Progressivism. Progressives inclined to resist Liberalism (...) are invited to consider an alternative position: the Libertarian stance that favors instead the ‘disestablishment’ of marriage. (shrink)