Asher, Herbert B. 1973. “The Learning of Legislative Norms.” American Political Science Review 67 (2): 499–513.CrossRefGoogle Scholar

Fleisher, Richard, and Bond, Jon R.. 2004. “The Shrinking Middle in the US Congress.” British Journal of Political Science 34: 429–451.CrossRefGoogle Scholar

Hacker, Jacob S., and Pierson, Paul. 2005. Off Center: The Republican Revolution and the Erosion of American Democracy. New Haven, CT: Yale University Press.Google Scholar

Lee, Frances E. 2009. Beyond Ideology: Politics, Principles, and Partisanship in the U.S. Senate. Chicago: University of Chicago Press.CrossRefGoogle Scholar

Mann, Thomas E., and Ornstein, Norman J.. 2012. It's Even Worse Than It Looks: How the American Constitutional System Collided with the New Politics of Extremism. New York: Basic Books.Google Scholar

Matthews, Donald R. 1960. U.S. Senators and Their World. Chapel Hill: University of North Carolina Press.Google Scholar

Poole, Keith T., and Rosenthal, Howard. 1997. Congress: A Political-Economic History of Roll Call Voting. New York: Oxford University Press.Google Scholar

Rohde, David, and Aldrich, John. 2010. “Consequences of Electoral and Institutional Change: The Evolution of the Conditional Party Government in the U.S. House of Representatives.” In Stonecash, Jeffrey M., ed., New Directions in American Political Parties. New York: Routledge.Google Scholar

Sinclair, Barbara. 2006. Party Wars: Polarization and the Politics of National Policy Making. Norman: University of Oklahoma Press.Google Scholar

Theriault, Sean M. 2013. The Gingrich Senators: The Roots of Partisan Warfare in Congress. New York: Oxford University Press.CrossRefGoogle Scholar

Theriault, Sean M. 2008. Party Polarization in Congress. New York: Cambridge University Press.CrossRefGoogle Scholar

Theriault, Sean M., and Rohde, David W.. 2011. “The Gingrich Senators and Party Polarization in the U.S. Senate.” Journal of Politics 73 (4): 1011–1024.CrossRefGoogle Scholar