Book excerpt: Polls and election results show Americans sharply divided on same-sex marriage, and the controversy is unlikely to subside anytime soon. Debating Same-Sex Marriage provides an indispensable roadmap to the ongoing debate. Taking a "point/counterpoint" approach, John Corvino (a philosopher and prominent gay advocate) and Maggie Gallagher (a nationally syndicated columnist and co-founder of the National Organization for Marriage) explore fundamental questions: What is marriage for? Is sexual difference essential to it? Why does the government sanction it? What are the implications of same-sex marriage for children's welfare, for religious freedom, and for our understanding of marriage itself? While the authors disagree on many points, they share the following conviction: Because marriage is a vital public institution, this issue deserves a comprehensive, rigorous, thoughtful debate.