Final answer:
The Dred Scott v. Sandford case in 1857 ruled that Black people could not be citizens and that Congress had no power to impede the expansion of slavery.
Step-by-step explanation:
The Dred Scott v. Sandford case, decided in 1857, was a Supreme Court case that ruled that Black people could not be citizens and that Congress had no jurisdiction to stop the expansion of slavery. Dred Scott, an enslaved African American, sued for his freedom after living in free territories. However, the court declared that Scott remained enslaved and that his time in free territory did not make him free. The decision also deemed parts of the Missouri Compromise, which restricted slavery in certain states, to be unconstitutional.