A gay marriage-style argument is now being used to peel back prohibitions on incestuous marriage. Steve Chapman, of the Chicago Tribune editorial board, has endorsed cousin marriage. The idea that the antiquity of cousin marriage in the Muslim Middle East somehow justifies cousin marriage in America is absurd. The same argument would justify polygamy and polyamory here. But of course, Chapman approves of those too. Actually, cousin marriage may be at the root of some of the problems in the Middle East, as I’ve argued elsewhere. But the real point is that cousin marriage in the Middle East has a totally different meaning than it would here. I addressed the issue of adult incest in “The Libertarian Question.” The interesting thing is that a columnist and a member of an important paper’s editorial board is making a public argument for cousin marriage. And all the recent talk about polyamory is nothing compared to what we’ll be seeing after a possible national establishment of same-sex marriage. With that safely done, the cultural left will feel free to openly press for more–much more. But right now, on polygamy and incest, Steve Chapman is leading the way.