On numerous occasions Congress had by statute excluded slavery from the public domain.

This, in the judgment of the Chief Justice, they had no right to do, and such legislation was unconstitutional and void.

Specifically the Missouri Compromise had never had any binding force as law.

Property in slaves was as sacred as property in any other form, and slave-owners had equal claim with other property owners to protection in all the Territories of the United States.

Neither Congress nor a territorial Legislature could infringe such equal rights.
According to popular understanding, the Supreme Court declared "that the negro has no rights which the white man is bound to respect." But Chief Justice Taney did not use these words merely as an expression of his own or of the Court's opinion.