At the Constitutional Convention, the delegates were concerned with the survival of the young nation. Many delegates called for strong protections for slavery, while many others hated the idea of putting into the Constitution the idea that there could be property in people. With the goal of forming a Union, they reached a compromise. Slave states would count 3/5ths of their slave populations towards their state populations to calculate taxation and representation in Congress. Additionally, Congress could not outlaw the international slave trade until 1808. The debate over the federal government's power to regulate slavery continued through the Civil War.
James Buchanan, Abraham Lincoln, and Andrew Johnson, who served as President of the United States in the years immediately before, during, and after the Civil War, each had different approaches to the constitutional powers of the President, if any, to interfere with the spread of slavery.