Answer:
that Congress did not have the power to prohibit slavery in any territory.
Step-by-step explanation:
In Dred Scott v. Sandford, the Supreme Court ruled that Americans who were African descendents, regardless if they were free or slave, were not considered to be American citizens and, as a result, they could not file a lawsuit in federal courts. The Court also ruled that Congress was not empowered to ban slavery in the territories of the United States. Finally, the Court decided that living in a free state, even for many years, did not free slaves, and declared the Missouri Compromise unconstitutional.
Dred Scott was a black slave who filed a lawsuit against Sandford so as to get his freedom. He argued that as he had lived in a free state, he was also a free man.
Northerners were against slavery. By means of this ruling, the Court benefited the southern states.