In March 1857 Chief Justice Roger B. Taney announced the opinion of the U.S. Supreme Court in Dred Scott v. John F. A. Sandford, which was the Court’s most important decision ever issued on slavery. The decision had a dramatic effect on American politics as well as law. The case involved a Missouri slave named Dred Scott who claimed to be free because his master had taken him to what was then the Wisconsin Territory and is today the state of Minnesota. In the Missouri Compromise (also known as the Compromise of 1820), Congress has declared that there would be no slavery north of the state of Missouri. Thus, Scott claimed to be free because he had lived in a federal territory where slavery was not allowed. In an opinion that was more than fifty pages long, Chief Justice Taney held that Scott was still a slave, that the Missouri Compromise was unconstitutional, and that Congress had no power to ban slavery from a federal territory.