American society is rapidly secularizing–a radical departure from its historically high level of religiosity–and politics is a big part of the reason. Just as, forty years ago, the Religious Right arose as a new political movement, today secularism is gaining traction as a distinct and politically energized identity. This book examines the political causes and political consequences of this secular surge, drawing on a wealth of original data. The authors show that secular identity is in part a reaction to the Religious Right. However, while the political impact of secularism is profound, there may not yet be a Secular Left to counterbalance the Religious Right. Secularism has introduced new tensions within the Democratic Party while adding oxygen to political polarization between Democrats and Republicans. Still there may be opportunities to reach common ground if politicians seek to forge coalitions that encompass both secular and religious Americans.