Is congressional politics a team sport? The rise of congressional partisanship poses several puzzles for those seeking to understand how Congress works. This book reveals and assesses these puzzles, notably, why would self-elected members delegate power to leaders? Why has congressional partisanship risen without any comparable change in electoral partisanship? Why would copartisans support party positions if leaders cannot enforce compliance? Finally, what are the effects of congressional parties? Congress, Parties, & Puzzles combines a strong theoretical framework with engaging illustrations and case studies so students can think more critically about how parties affect Congress and how voters should assess their elected officials.