Well, according to the Dred Scott decision the northern states had to give back runaway slaves because freeing them would be an unconstitutional taking of private property ala the Fourth Amendment. One of the worst decisions in SCOTUS history that was a major cause of the civil war, but for a time it was considered a constitutional right.
Not really. One part of the Dred Scott decision was the requirement that the Federal Government enforce the provisions of the Fugitive Slave Act of 1950. This legislation required States and local governments cooperate in apprehension and return of runaway slaves.