When President Lincoln first called for troops to put down the confederate rebellion, he made no connection between this action and an attempt to end slavery. In fact, he explicitly stated "the utmost care will be observed to avoid any devastation, any destruction of, or interference with, property..." At this point, slavery was not yet integral to the struggle, it was much more important for the Union to air on the side of political prudence and avoid angering loyal boarder states. However, despite this lack of political dialogue, many abolitionists, slaves, and free blacks felt the war to preserve the union could also be a war to end slavery. In the end, they were right, as military need overwhelmed potential political dangers, slaves and the institution of slavery became a central issue in the civil war.
In congruence with President Lincoln’s statements regarding the differentiation between fighting the confederates and ending slavery, Union officers upheld slaveholders constitutionally guaranteed right to own slaves. They continually reassured slave holders in loyal boarder states that the Union would not be fighting against the institution of slavery and any runaway slaves would be returned. This policy was strictly followed by most generals and many runaway slaves were returned to their masters to face punishment or death. Despite this danger, slaves continued to run away and enter Union lines. As this persisted, many Union officers were forced to reconsider the official policy of their superiors. General Benjamin F. Butler was one of the first to break the trend, providing food and shelter to slaves who had previously worked for the Confederacy, and ultimately putting the able-bodied men to work. He justified his actions partially through a rhetorical question, "Shall [the confederates] be allowed the use of this property against the United States, and we not be allowed its use in aid of the United States!" He further argued that he was "in great need of labor" and the Union might make use of slaves without violating its promise to loyal slaveholders.
This rationale was ultimately accepted by the Secretary of War, Simon Cameron. Who acknowledged that “no ‘Federal obligations’ outweighed the suppression of armed rebellion.” These arguments were even more persuasive following the Union’s defeat at the battle of Bull Run. As Congress began to realize victory may be years away, and every available resource had to be utilized, they passed the First Confiscation Act. This act declared that any piece of property, including slaves, used against the Union may be “subject of prize and capture wherever found.”
Although this gave officers legal justification for employing runaway slave labor, and emboldened many slaves to flee, there still had to be a balance between the interests of the Union army and the interests of loyal slaveholders. The First Confiscation Act only allowed for the requisition of slaves employed for the Confederate...