Marriage is at the center of one of today's fiercest political debates. Activists argue about how to define it, judges and legislators decide who should benefit from it, and scholars consider how the state should protect those who are denied it. Few, however, ask whether the state should have anything to do with marriage in the first place. In Untying the Knot, Tamara Metz addresses this crucial question, making a powerful argument that marriage, like religion, should be separated from the state. Rather than defining or conferring marriage, or relying on it to achieve legitimate...