Final answer:
The Supreme Court case that ruled African Americans were not citizens and that the federal government had no authority to regulate slavery in the territories is Dred Scott v Sandford.
Step-by-step explanation:
The Supreme Court case that ruled African Americans were not citizens and that the federal government had no authority to regulate slavery in the territories is Dred Scott v Sandford. In this case, which was decided in 1857, the Court held that African Americans, whether enslaved or free, were not citizens and therefore did not have the right to sue in federal court. The decision also stated that Congress had no power to prohibit slavery in the territories.
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