Final answer:
Abraham Lincoln led the United States during the Civil War, which resulted in the abolition of slavery.
Step-by-step explanation:
Abraham Lincoln led the United States during the Civil War. This was an important role because the Civil War was a major conflict between the Northern and Southern states over slavery and states' rights. Lincoln's leadership and the Union's victory ultimately led to the abolition of slavery in the United States.
Learn more about Abraham Lincoln's leadership during the Civil War