The Dred Scott v. Sandford case of 1857 was a landmark Supreme Court decision with profound implications. The court ruled that Dred Scott, an enslaved man, was not a citizen and therefore could not sue in federal court. The ruling further stated that Congress had no authority to prohibit slavery in the territories, effectively nullifying the Missouri Compromise of 1820. This decision heightened tensions over slavery, deepening the divide between the North and South and contributing to the rise of the abolitionist movement. It also underscored the limitations of legal protections for African Americans and set a troubling precedent for civil rights in America.