Alan Stewart Carl has a great retort to Justin Gardner's case for polygamy based on a column by Katherine Kersten, a conservative columnist for the Minneapolis Star Tribune. She trots out the tired old argument that any approval of gay marriage would lead to polygamy.
Now, I know some gay men who are in polyarmous relationship and it works well. But I agree with Alan: most of these polygamous marriages are exploitative of women. Gay marriage is basically the same old, same old, just with two people of the same sex. In theory it might seem nice and wonderful, but in reality , for the most part, is not as nice.
Also, this doesn't help those of us are gay and want to be married at some point. The far right can use this to tell us that we are a threat and lead America down a path to Sodom. Middle America is trying to deal with gay marriage; it would be difficult if not impossible to get Americans to deal with guy who wants to marry three women.
I think, those who care about gay marriage needs to stay away from this polygamy trap.