...Only with the firing on Fort Sumter did the abolitionists and Lincoln find common ground in resisting the rebellion, but their differences on what to do about slavery soon drove them apart again. Abolitionists argued that the government was justified in divesting rebels of their slaves, but Lincoln insisted on delaying such a measure until sufficient popular support could be mustered, and then he would only consent to emancipation as a strictly military measure, justified by his constitutional war powers as commander in chief. With his Emancipation Proclamation of 1863, Lincoln succeeded in winning over many of the most influential abolitionists, including the man who had once called the Constitution “a covenant with death and an agreement with Hell,” William Lloyd Garrison. By pushing hard for passage of the Thirteenth Amendment to the Constitution, which outlawed slavery, Lincoln arrived, at long last, at a definitive point of agreement with the abolitionists.
