Dred Scott v. Sandford, , was a landmark decision by the U.S. Supreme Court in which the Court held that African Americans, whether enslaved or free, could not be American citizens and therefore had no standing to sue in federal court, and that the federal government had no power to regulate slavery in the federal territories acquired after the creation of the United States. Dred Scott, an enslaved African American man who had been taken by his owners to free states and territories, attempted to sue for his freedom. In a 7–2 decision written by Chief Justice Roger B. Taney, the Court denied Scott's request. For only the second time to that point in its history, the Supreme Court ruled an Act of Congress to be unconstitutional.