The Circassian was a case heard by the United States Supreme Court in 1864. The court had to decide whether or not an African American man, who had been born into slavery and later purchased his freedom, could be considered a citizen of the United States. The plaintiff argued that he should be recognized as a citizen because he was free when the Civil War began and therefore entitled to all rights under the Constitution. However, the defendant argued that since he had been born into slavery, he did not qualify for citizenship status. After considering both sides of this argument, the Supreme Court ultimately ruled in favor of recognizing him as a citizen due to his purchase of freedom prior to war breaking out between North and South America during 1861-1865. This decision set an important precedent for future cases involving African Americans seeking recognition as citizens with full constitutional rights regardless of their past enslavement status.

In The Circassian, the Supreme Court was asked to decide whether a ship that had been seized by Confederate forces during the Civil War could be considered a prize of war. In an 8-1 decision, the court held that it could not. Chief Justice Salmon P. Chase wrote for the majority and argued that since Congress had declared neutrality in 1861, any seizure of property from either side would have violated international law and thus should not be recognized as valid under U.S. law or given legal effect in American courts. He further noted that even if such seizures were allowed to stand they would still need to meet certain criteria before being deemed lawful prizes of war; namely, they must have been taken with proper authority and without fraud or collusion between captors and claimants on either side of the conflict. Since this case did not meet these requirements it was determined invalid as a prize of war under U.S law despite having already been adjudicated by foreign tribunals prior to its appeal at the Supreme Court level.. Justice David Davis dissented from this opinion arguing instead for recognition based on comity among nations which he felt should take precedence over domestic laws when dealing with matters concerning international relations