This thoughtfully updated revision of a classic text sheds new light on the potential sociological and biological differences that result in deep, seemingly unbridgeable political divisions.Renowned social scientists and experts in biopolitics, John R. Hibbing, Kevin B. Smith, and John R. Alford present overwhelming evidence that political opinion is shaped not just by cultural background or information bias but is rather the result of diverse psychological, physiological, and genetic traits. This new edition shifts the emphasis from differences between the political left and the right (liberals and conservatives) as they have traditionally been understood and explores specific brands of liberalism and conservatism such as ardent supporters of politicians such as Donald Trump.An essential read for students and scholars of political psychology and party politics, this book invites the reader to reconsider their perspectives on public opinion and partisan conflict.