Winning presidential elections isn’t just about the ballot box; it is shaped by the rules of the “apportionment game.” Shifting Seats uncovers the gritty history of how politicians fought for greater legislative influence and how those decisions determined control of Congress—and sometimes the presidency. Moving beyond abstract debates, Keith L. Dougherty takes readers inside high-stakes bargaining from the Founding era, the Antebellum period, and post–Civil War struggles over representation. Within these periods, Dougherty models how legislators manipulated the building blocks of apportionment—including metrics, ratios, House sizes, and rounding methods—to maximize their state’s proportion of seats. He explains how a 1920s stalemate fixed the House’s size at 435 members and created the automatic system in use today. 
Bridging the gap between political history and formal theory, the book identifies the long-term mechanisms that stabilize or disrupt distributions of power. Further, it shows how different apportionment methods could have flipped some presidential elections. By connecting these clashes to our current polarized climate, Shifting Seats explains why some apportionment rules endure while others fail, revealing the hidden mechanics that continue to dictate the balance of power in Washington today.