Explain the Supreme Court ruling in the Dred Scott decision?

The Supreme Court ruling in the Dred Scott decision declared that African Americans, whether enslaved or free, were not considered United States citizens and therefore could not sue in federal court. The ruling also stated that the Missouri Compromise of 1820, which restricted slavery in certain territories, was unconstitutional. This decision further inflamed tensions regarding slavery in the United States and is widely recognized as one of the worst rulings in the Court's history.