In the late 1840s, Representative Abraham Lincoln resided on Capitol Hill at Mrs. Sprigg's boardinghouse, known as "Abolition House," where congressional boarders held lively dinner-table debates of antislavery politics. From the White House, just 12 years later, Lincoln could see the Confederate flag flying just across the Potomac. Washington, D.C., was literally on the front line of the Civil War, and the city was rife with Confederate sympathizers. Kenneth Winkle takes us back to the capital in war, vividly observing how the Lincoln administration met the immense challenges posed to the vulnerable city, transforming it into a bastion for the Union.