What did dred Scott say was unconstitutional?

Dred Scott argued that the Missouri Compromise, which restricted the expansion of slavery into certain territories, was unconstitutional. He claimed that this limitation violated his rights as a U.S. citizen, asserting that he should be free because he had lived in free territories. The Supreme Court ultimately ruled against Scott, declaring that African Americans could not be considered citizens and that Congress lacked the authority to regulate slavery in the territories.