In the past I used to counter any such notions by asking myself: 'Would you really want President Hattersley?' I now find that possibility rather cheers me up. With his chubby Dickensian features and his knowledge of T.H. Green and other harmless leftish political classics Hattersley might not be such a bad thing after all.
The state's interest in marriage is stability. Generally speaking polygamy does not work for stability. Inherent in the whole polygamous movement is a deep and abiding misogyny and denigration of women. So polygamy is objectionable on lots of grounds.