Gay Marriage Makes Legalized Polygamy Inevitable argues Colby Cosh. All right-thinking folks say, "Horrors, no, while the word "marriage" doesn't imply two sexes, it can't possibly imply more than two people." Colby replies, "Yeah, right ..."
By the way, nobody else noticed it but Spike Lee's most recent movie She Hate Me was built on exactly that gay marriage --> polygamy logic. Spike's not too crazy about gay marriage, but he thinks it definitely justifies what he's enthusiastic for: polygamy. Here's my review of She Hate Me.
By the way, Colby, please do my 46-year-old eyes a favor and use a larger typeface on your blog.