Final answer:
Lincoln's major challenge at the start of the Civil War was preventing local leaders in the North from aiding the Confederacy, and deciding what to do with the freed slaves. As the number of escaped enslaved people grew, Lincoln and Congress were forced to take action.
Step-by-step explanation:
One of President Lincoln's major challenges at the start of the Civil War was preventing local leaders in the North from aiding the Confederacy.
Likewise, during the early years of the war, Lincoln also believed that any slaves freed as a consequence of the war, or by the volition of their masters, should be resettled outside of the United States.
However, as the number of escaped enslaved people seeking refuge behind Union army lines grew, Lincoln and Congress were forced to address the issue.