In early 1864, the Federal Army made plans to destroy the Confederate military once and for all. Union armies led by Ulysses S. Grant (1822–1885) and William T. Sherman (1820–1891) launched offensives deep into Confederate territory with the specific purpose of wiping out the South's major remaining armies. This strategy enjoyed support throughout the North, which had become confident of victory after the Union triumphs of 1863. By midsummer, however, Northern confidence wavered as Confederate defiance stayed strong. Dissatisfaction with Grant's campaign was particularly strong, since he racked up very high casualty rates in his effort to break the Confederate Army of Northern Virginia, led by Robert E. Lee (1807–1870).

As the 1864 U.S. presidential elections drew near, many people believed that war-weary Northerners would vote to replace President Abraham Lincoln (1809–1865) with Democratic candidate George B. McClellan (1826–1885), the former general of the Army of the...