The story of how Congress helped win the Civil War--a new perspective that puts the House and Senate, rather than Lincoln, at the center of the conflict. This brilliantly argued new perspective on the Civil War overturns the popular conception that Abraham Lincoln single-handedly led the Union to victory and gives us a vivid account of the essential role Congress played in winning the war. Building a riveting narrative around four influential members of Congress--Thaddeus Stevens, Pitt Fessenden, Ben Wade, and the proslavery Clement Vallandigham--Fergus Bordewich shows us how a newly empowered Republican party shaped one of the most dynamic and consequential periods in American history. From reinventing the nation's financial system to pushing President Lincoln to emancipate the slaves to the planning for Reconstruction, Congress undertook drastic measures to defeat the Confederacy, in the process laying the foundation for a strong central government that came fully into being in the twentieth century. Brimming with drama and outsize characters, Congress at War is also one of the most original books about the Civil War to appear in years and will change the way we understand the conflict.