Answer:
4. The case resulted in the Supreme Court denying that African Americans could be citizens and added to the sectional tensions that eventually led to the Civil War.
The Dred Scott v. Sandford case is significant in American history because it further entrenched the idea that African Americans, whether enslaved or free, could not be considered citizens of the United States. The Supreme Court's ruling intensified sectional tensions between the North and the South over the issue of slavery, contributing to the broader context that eventually led to the outbreak of the Civil War.