Brown v. Bass was a United States Supreme Court case that was decided in 1866. The case involved a dispute between two parties over the ownership of a slave. The plaintiff, Brown, claimed that he had purchased the slave from the defendant, Bass, and that Bass had failed to deliver the slave to him. Bass argued that he had never sold the slave to Brown and that the slave was still his property. The Supreme Court ultimately sided with Brown, ruling that Bass had indeed sold the slave to Brown and that Brown was the rightful owner. The Court held that the sale was valid and binding, and that Bass had no right to reclaim the slave. The Court also held that the sale was not invalidated by the fact that slavery had been abolished in the United States. The decision in Brown v. Bass was significant because it established that contracts involving the sale of slaves were still valid and enforceable, even after the abolition of slavery. This ruling was important in helping to ensure that the rights of former slaves were respected and protected.

In Brown v. Bass, the Supreme Court was tasked with determining whether a slave who had been emancipated by his master in Virginia could be re-enslaved after moving to North Carolina. The majority opinion held that he could not, as the laws of North Carolina did not recognize slavery and therefore any attempt to enslave him would be illegal. In dissent, Justice Nelson argued that since slavery was recognized under both federal and state law at the time of emancipation in Virginia, it should also be recognized when Brown moved to North Carolina. He reasoned that if slaves were considered property under one jurisdiction then they should remain so regardless of where they traveled within the United States; otherwise their status would depend on which state or territory they happened to reside in at any given moment. Furthermore, Nelson argued that allowing states like North Carolina to ignore other states' laws regarding slavery would lead to chaos and confusion among citizens trying determine what rights applied where for themselves or their property.