In America’s Struggle for Same-Sex Marriage, Daniel Pinello explores the social and political underpinnings of the controversy surrounding so-called “gay” marriage. Pinello’s analysis is directed toward using the struggle for marriage equality as an empirical basis for achieving a better understanding of how public policy derives from the interactions of citizens, interest groups, and government entities. This Book Review argues the importance to policy formation of a force Pinello tends to underemphasize: the counter-majoritarian influence of constitutional law and judicial review. The significance of this factor is considered primarily in relation to state constitutional amendments that purport to “define” marriage as being strictly between one man and one woman. This Book Review concludes that such amendments, by their nature, violate the Federal Equal Protection Clause. Separate consideration is given to the particular illegitimacy and vulnerability of such an amendment in Massachusetts, where state constitutional jurisprudence requires equal marriage rights for same-sex couples.