ABSTRACT
This chapter reviews the main academic explanations for the origins and persistence of partisan polarization in Congress, identifying mass-level and elite-level forces that began to unfold in the 1970s and continue to matter today. I then discuss some of the consequences of polarization for both legislative outcomes and the policymaking process. I also review a variety of reforms that have been proposed and discuss their likely effects on legislative polarization. The conclusion addresses a few tensions between academic research and popular perceptions of polarization and outlines a variety of future directions for polarization research.
