In the earliest days of the Civil War, the Union Army focused on cutting off key supply lines on the periphery of the South. The approach was designed to hurt the South's economy and convince its citizens to return to the Union.
Even though President Lincoln said slavery was unjust, in the earliest days of the war he told the Southern states that he wouldn't interfere with slavery as an institution.
"He believed that with ... leaving slavery alone, that he could convince the Southern majority — Southern moderates — to come back," says Wesleyan professor and historian Richard Slotkin. "It took a year of conflict for him to realize that Southerners were really committed to the Confederacy."
Slotkin's latest book about the Civil War, The Long Road to Antietam, traces how both Northern and Southern strategies changed in the summer of 1862, when both sides committed to an all-out total war and Lincoln squared off against Gen. George McClellan, an ardent Democrat who held fantasies of both a dictatorship and a military coup against the Union.
After a battle in Virginia, McClellan, who briefly served as the chief general of the Union Army and organized the Army of the Potomac, demanded that Lincoln reject any move against slavery, stop treating Southerners as rebels and give up his own political power.
"Within a week, Lincoln rejected those demands and told [another general] that he was going to issue an Emancipation Proclamation, which was opposed to everything McClellan had just said to him," Slotkin tells Fresh Air's Dave Davies. "The decision to issue an Emancipation Proclamation meant [he was] throwing out any hope of compromise with the South."
In making that decision, Slotkin says Lincoln knew he was turning the Civil War into a much bigger conflict. "The South would not quit until beaten, and that means total war."