The Dred Scott case was a series of court cases that eventually reached the Supreme Court of the United States. The main issue in the case was whether African Americans could be citizens of the United States. The Supreme Court ruled in favor of the defendants, Dred Scott and Harriet Scott, and found that they were not citizens and could not sue in federal court. This decision was widely unpopular and contributed to the growing tensions between the North and South that eventually led to the Civil War.