Gary C. Jacobson is Distinguished Emeritus Professor of Political Science at UCSD. His field of interest is American national politics, with a subfield focus on Congress and congressional elections. He is the author of Money in Congressional Elections; The Politics of Congressional Elections; and The Electoral Origins of Divided Government; and co-author of Strategy and Choice in Congressional Elections, American Parties in Decline, and The Logic of American Politics. His current research is on the electoral basis of partisan polarization in Congress. Jamie Carson is professor of political science at the University of Georgia. His research interests include American politics and methods. He regularly teaches courses on the U.S. Congress, the presidency, the politics of congressional elections, and American political development. Recent books include (with Joel Sievert) Electoral Incentives in Congress (2018); John H. Aldrich, Jamie L. Carson, Brad T. Gomez, and David W. Rohde Change and Continuity in the 2016 Elections (2018).