In the Supreme Court case Dred Scott v. Sandford, what was Scott's claim?

In Dred Scott v. Sandford (argued 1856 - - decided 1857), the Supreme Court ruled that Americans of African descent, whether free or slave, were not American citizens and could not sue in federal court. The Court also ruled that Congress lacked power to ban slavery in the U. S. territories.

That his time in a free territory meant that he was a free man