Paul Varnell fisks marriage equality opponents. A snippet:

Homophobes like to argue that if we legalize gay civil marriage it will lead to heterosexual polygamy. As usual with homophobes, they have things backwards. For much of recorded history, marriage was a man and a number of women, depending on the man's economic status. Any reader of the Old Testament knows this. That tradition continues to this day in Muslim countries and existed for several decades among Mormons in the U.S. So, as same-sex marriage becomes a reality, we can accurately say that polygamy preceded same-sex marriage, not followed as a result.