During the 2008 US Presidential election, voters in California, as well as choosing a president, were asked to withdraw the right of same-sex couples to marry, the Californian Supreme Court having, six months previously, conferred that right by judicial decision.1 ‘Proposition 8’ aimed to restore the definition of marriage to its historical heterosexual limitations, and it passed, by a fairly narrow margin. The feature most remarkable to an outsider during the Proposition 8 campaign was the stunningly apocalyptical terms in which the debate was conducted, on both sides of the argument. The same-sex marriage debate is in the United States of America conducted in such venomous terms as to leave a European observer quite breathless. Nancy Polikoff’s latest book brings some calm to the discussion. It is a measured and thoughtful contribution to the debate and, though she does not directly address the question of why it is so much more contentious in the US than in other Western jurisdictions, her analysis does shed much light on that puzzling question. There are three main explanations that spring out of this engaging book.