McPherson asserts that the abolition of enslavement and the preservation of the Union were inextricably linked. He begins by analyzing Gary Gallagher’s The Union War. Although McPherson finds value in Gallagher’s delineation of the meaning of “Union” to mid-19th century Americans, he nonetheless takes issue with Gallagher’s presentation of abolition as a mere by-product of the Union cause. McPherson presents evidence that Union intentionality regarding the abolition of enslavement occurred as early as 1861; he cites the fact that Republican leaders and constituents suggested to Lincoln that enslavement and the Union were incompatible and emphasizes Major General Benjamin Butler’s decision to receive enslaved people who escaped to Union lines as contraband of war. This early intention grew considerably as the war continued, and the Union and abolition causes were fused by 1864. 

Lincoln’s adoption of Butler’s pivotal policy and the infusion of Black soldiers into Union camps give rise to the question of whether it is Black people and their initiative to escape or Lincoln and the Emancipation Proclamation that deserve primary credit for abolition. McPherson discusses the self-emancipation thesis that dominated the 1980s, but he concludes that Lincoln is more directly responsible because the Emancipation Proclamation converted the Union army to a liberation army, and the 13th Amendment freed 3.