James A. Thurber is University Distinguished Professor of Government and Founder and Director of the Center for Congressional and Presidential Studies at American University, Washington DC. In 2010, he won the Walter Beach Pi Sigma American Political Science Association Award for his work combining applied and academic research. He is a Fellow of the National Academy of Public Administration and a member of the American Bar Association's Task Force on Lobbying Law Reform. He is the author of multiple books and more than eighty articles and chapters on Congress, congressional-presidential relations, congressional budgeting, congressional reform, interest groups and lobbying, congressional ethics, and campaigns and elections. He co-produced three BBC TV documentaries on the US Congress and elections. Antoine Yoshinaka is Associate Professor in the Department of Political Science at the State University of New York, Buffalo. He has published numerous articles on elections, parties, and representation in outlets like PS: Political Science and Politics, Legislative Studies Quarterly, the British Journal of Political Science and Electoral Studies. His book Crossing the Aisle: Party Switching by US Legislators in the Postwar Era was published by Cambridge University Press in 2015.

• Part I. Polarization among Voters and Activists: 1. The new American electorate: partisan, sorted, and polarized Alan I. Abramowitz; 2. Redistricting and polarization Micah Altman and Michael McDonald; 3. Party activists, interest groups, and polarization in American politics David Karol; 4. Authoritarianism and polarization in American politics, still? Marc J. Hetherington and Jonathan Weiler; 5. Party sorting: the foundation of polarized politics Samuel J. Abrams and Morris P. Fiorina; Part II. Polarization in National Institutions: 6. Presidential-congressional relations in an era of polarized parties and a sixty-vote Senate Jon R. Bond, Richard Fleisher and Jeffrey E. Cohen; 7. Party warriors: the ugly side of party polarization in Congress Sean M. Theriault; 8. The sources and consequences of polarization in the US Supreme Court Brandon L. Bartels; Part III. Polarization in the States: 9. Polarization in American state legislatures Boris Shor; 10. The costs of party reform: two states' experiences Seth E. Masket; 11. The policy consequences of party polarization: evidence from the American States Elizabeth Rigby and Gerald C. Wright; Part IV. Polarization in the Media: 12. Partisan media and electoral polarization in 2012: evidence from the American National Election Study Gary C. Jacobson; 13. News as a casualty: district polarization and media coverage of US House campaigns Danny Hayes and Jennifer L. Lawless; 14. More a symptom than a cause: polarization and partisan news media in America Kevin Arceneaux and Martin Johnson; 15. The polarizing effects of partisan and mainstream news Natalie Jomini Stroud and Alexander Curry; Part V. Implications and Conclusions: 16. Congressional polarization and its connection to income equality: an update Adam Bonica, Nolan McCarty, Keith T. Poole and Howard Rosenthal; 17. The sources and impact of political polarization James A. Thurber and Antoine Yoshinaka.

'American Gridlock is a collection of work from some of the best scholars who study American political polarization. These impressive thinkers join together to explore polarization in the US electorate, political institutions, states, and the media, all in one volume. This is a must-have book for anyone interested in American politics in the current era.' Joseph Bafumi, Dartmouth College

James A. Thurber is University Distinguished Professor of Government and Founder and Director of the Center for Congressional and Presidential Studies at American University, Washington DC. In 2010, he won the Walter Beach Pi Sigma American Political Science Association Award for his work combining applied and academic research. He is a Fellow of the National Academy of Public Administration and a member of the American Bar Association's Task Force on Lobbying Law Reform. He is the author of multiple books and more than eighty articles and chapters on Congress, congressional-presidential relations, congressional budgeting, congressional reform, interest groups and lobbying, congressional ethics, and campaigns and elections. He co-produced three BBC TV documentaries on the US Congress and elections. Antoine Yoshinaka is Associate Professor in the Department of Political Science at the State University of New York, Buffalo. He has published numerous articles on elections, parties, and representation in outlets like PS: Political Science and Politics, Legislative Studies Quarterly, the British Journal of Political Science and Electoral Studies. His book Crossing the Aisle: Party Switching by US Legislators in the Postwar Era was published by Cambridge University Press in 2015.

• Part I. Polarization among Voters and Activists: 1. The new American electorate: partisan, sorted, and polarized Alan I. Abramowitz; 2. Redistricting and polarization Micah Altman and Michael McDonald; 3. Party activists, interest groups, and polarization in American politics David Karol; 4. Authoritarianism and polarization in American politics, still? Marc J. Hetherington and Jonathan Weiler; 5. Party sorting: the foundation of polarized politics Samuel J. Abrams and Morris P. Fiorina; Part II. Polarization in National Institutions: 6. Presidential-congressional relations in an era of polarized parties and a sixty-vote Senate Jon R. Bond, Richard Fleisher and Jeffrey E. Cohen; 7. Party warriors: the ugly side of party polarization in Congress Sean M. Theriault; 8. The sources and consequences of polarization in the US Supreme Court Brandon L. Bartels; Part III. Polarization in the States: 9. Polarization in American state legislatures Boris Shor; 10. The costs of party reform: two states' experiences Seth E. Masket; 11. The policy consequences of party polarization: evidence from the American States Elizabeth Rigby and Gerald C. Wright; Part IV. Polarization in the Media: 12. Partisan media and electoral polarization in 2012: evidence from the American National Election Study Gary C. Jacobson; 13. News as a casualty: district polarization and media coverage of US House campaigns Danny Hayes and Jennifer L. Lawless; 14. More a symptom than a cause: polarization and partisan news media in America Kevin Arceneaux and Martin Johnson; 15. The polarizing effects of partisan and mainstream news Natalie Jomini Stroud and Alexander Curry; Part V. Implications and Conclusions: 16. Congressional polarization and its connection to income equality: an update Adam Bonica, Nolan McCarty, Keith T. Poole and Howard Rosenthal; 17. The sources and impact of political polarization James A. Thurber and Antoine Yoshinaka.

'American Gridlock is a collection of work from some of the best scholars who study American political polarization. These impressive thinkers join together to explore polarization in the US electorate, political institutions, states, and the media, all in one volume. This is a must-have book for anyone interested in American politics in the current era.' Joseph Bafumi, Dartmouth College

James A. Thurber is University Distinguished Professor of Government and Founder and Director of the Center for Congressional and Presidential Studies at American University, Washington DC. In 2010, he won the Walter Beach Pi Sigma American Political Science Association Award for his work combining applied and academic research. He is a Fellow of the National Academy of Public Administration and a member of the American Bar Association's Task Force on Lobbying Law Reform. He is the author of multiple books and more than eighty articles and chapters on Congress, congressional-presidential relations, congressional budgeting, congressional reform, interest groups and lobbying, congressional ethics, and campaigns and elections. He co-produced three BBC TV documentaries on the US Congress and elections. Antoine Yoshinaka is Associate Professor in the Department of Political Science at the State University of New York, Buffalo. He has published numerous articles on elections, parties, and representation in outlets like PS: Political Science and Politics, Legislative Studies Quarterly, the British Journal of Political Science and Electoral Studies. His book Crossing the Aisle: Party Switching by US Legislators in the Postwar Era was published by Cambridge University Press in 2015.

• Part I. Polarization among Voters and Activists: 1. The new American electorate: partisan, sorted, and polarized Alan I. Abramowitz; 2. Redistricting and polarization Micah Altman and Michael McDonald; 3. Party activists, interest groups, and polarization in American politics David Karol; 4. Authoritarianism and polarization in American politics, still? Marc J. Hetherington and Jonathan Weiler; 5. Party sorting: the foundation of polarized politics Samuel J. Abrams and Morris P. Fiorina; Part II. Polarization in National Institutions: 6. Presidential-congressional relations in an era of polarized parties and a sixty-vote Senate Jon R. Bond, Richard Fleisher and Jeffrey E. Cohen; 7. Party warriors: the ugly side of party polarization in Congress Sean M. Theriault; 8. The sources and consequences of polarization in the US Supreme Court Brandon L. Bartels; Part III. Polarization in the States: 9. Polarization in American state legislatures Boris Shor; 10. The costs of party reform: two states' experiences Seth E. Masket; 11. The policy consequences of party polarization: evidence from the American States Elizabeth Rigby and Gerald C. Wright; Part IV. Polarization in the Media: 12. Partisan media and electoral polarization in 2012: evidence from the American National Election Study Gary C. Jacobson; 13. News as a casualty: district polarization and media coverage of US House campaigns Danny Hayes and Jennifer L. Lawless; 14. More a symptom than a cause: polarization and partisan news media in America Kevin Arceneaux and Martin Johnson; 15. The polarizing effects of partisan and mainstream news Natalie Jomini Stroud and Alexander Curry; Part V. Implications and Conclusions: 16. Congressional polarization and its connection to income equality: an update Adam Bonica, Nolan McCarty, Keith T. Poole and Howard Rosenthal; 17. The sources and impact of political polarization James A. Thurber and Antoine Yoshinaka.

'American Gridlock is a collection of work from some of the best scholars who study American political polarization. These impressive thinkers join together to explore polarization in the US electorate, political institutions, states, and the media, all in one volume. This is a must-have book for anyone interested in American politics in the current era.' Joseph Bafumi, Dartmouth College