An excellent article from James Milliken, Jr. at American Thinker:
Referenda on changing the legal definition of marriage to include same-sex relationships have become a recurrent feature of our electoral landscape in recent years. Voters have rejected the proposed changes every time, but the margins are narrowing; even conservative voters, particularly those of a libertarian bent, are beginning to conclude that “gay marriage” is not that big a deal, or even that redefining marriage advances freedom. They could not be more wrong: redefining marriage is indeed a big deal, which is not only a threat to liberty, but a significant step in the direction of totalitarian tyranny.
Despite thirty-plus campaigns, there has been little informed public discussion about what marriage is and the state’s interest in maintaining traditional marriage (sadly, the proponents of redefining marriage prefer to rely on name-calling and intimidation, which leaves little room for dispassionate debate). As a consequence, many voters have never heard the actual arguments in defense of traditional marriage, but only the strawmen that its opponents are fond of pummeling, most of which (on the surface) appeal to the idea of freedom.