Dred Scott case: the Supreme Court decision
There are two leading questions presented by the record:
1) Had the Circuit Court of the United States jurisdiction to hear and determine the case between these parties? And
2) If it had jurisdiction, is the judgment it has given erroneous or not?
...
The plaintiff [Dred Scott]... was, with his wife and children, held as slaves by the defendant [Sanford], in the State of Missouri; and he brought this action in the Circuit Court of the United States for [Missouri], to assert the title of himself and his family to freedom.
The declaration is . . . that he and the defendant are citizens of different States; that... he is a citizen of Missouri, and the defendant a citizen of New York.
...
The question is simply this: Can a negro, whose ancestors were imported into this country, and sold as slaves, become a member of the political community formed and brought into existence by the Constitution of the United States, and as such become entitled to all the rights, and privileges, and immunities, guarantied by that instrument to the citizen? One of which rights is the privilege of suing in a court of the United States in the cases specified in the Constitution....
http://www.pbs.org/wgbh/aia/part4/4h2933t.html