The antebellum period was filled with important Supreme Court decisions that had an influential impact on the United States. The Dred Scott v. Sandford case is a perfect example of a decision that greatly affected the United States. In Dred Scott v. Sandford, the Supreme Court ruled that African Americans, whether slave or free, were not U.S. citizens and could not sue in federal court. The Court also ruled that Congress did not have the authority to prohibit slavery in U.S. territories. Additionally, the Court also ruled that the Fifth Amendment protected the rights of slave owners because slaves were not classified as humans but as property. The devastating outcome of this trial had multiple effects on the United States; it gave more power to the national government, it took away some state sovereignty, overturned the Missouri Compromise, started the Civil War, and opened the eyes of Northerners. Dred Scott v. Sandford was a very influential case in the midst of the Civil War. 1800s. The affair took place in 1857; however, the events leading up to it began in 1833. Dr. John Emerson had bo...