Justice Sonia Sotomayor was questioning former U.S. Solicitor General Ted Olson, a pro-gay marriage Republican. She brought up a very interesting question during the exchange: If gay marriage is legal, what about polygamy? Sotomayor asked, "If you say that marriage is a fundamental right, what state restrictions could ever exist?" before referencing "polygamy and incest among adults," as reported by Matt Canham of the Salt Lake Tribune. The argument is an illustration of a broader issue about the culture of American society. To agree that gay marriage is indeed protected by the "equal protection" clause in the Constitution, wouldn't the...