The vast Union army quickly disappeared in the months after the Confederate surrender. From one million men in the spring of 1865, the army shrunk to less than 200,000 by the end of the year. Nevertheless, the bitter divide between the North and the South continued for many years after the war, and many believe it continues to the present day. Northern armies occupied southern cities until new governments were installed that would abolish slavery and swear loyalty to the Union. These reconstruction governments were met with great hostility among Southerners, who resented the Northern "carpetbaggers" who had arrived to rule over them. The Emancipation Proclamation brought freedom, but not equality, for Southern blacks, who were still denied legal rights to landownership, voting, education, and occupation. It was not until 1877 that all of the former Confederate states had returned to the Union.

After the war, the...