The Ouachita Cotton case was a United States Supreme Court case that was decided in 1867. The case involved a dispute between the United States and the State of Louisiana over the ownership of a cotton bale that had been seized by the United States during the Civil War. The United States argued that the cotton bale had been seized as a prize of war and was therefore the property of the United States. The State of Louisiana argued that the cotton bale was the property of a private individual and should be returned to him. The Supreme Court ultimately sided with the United States, ruling that the cotton bale was the property of the United States and that the State of Louisiana had no right to interfere with the seizure. The Court held that the seizure was a valid exercise of the United States' war powers and that the State of Louisiana had no authority to interfere with the seizure. The Court also held that the United States had the right to seize the cotton bale as a prize of war and that the State of Louisiana had no right to interfere with the seizure. The Court also held that the United States had the right to dispose of the cotton bale as it saw fit.

In the case of The Ouachita Cotton, the Supreme Court was asked to decide whether a contract between two parties that had been made in Louisiana before it became part of the United States should be enforced. The majority opinion held that since Louisiana was not yet part of the US when this contract was entered into, it could not be enforced under federal law. However, Justice Field dissented from this opinion and argued that even though Louisiana had not yet become a state at the time of contracting, its laws were still valid and binding on both parties. He further argued that if Congress intended for such contracts to be unenforceable after admission into union then they would have explicitly stated so in their enabling act or other legislation governing admission. As no such language existed he concluded that these pre-admission contracts should remain enforceable by virtue of being recognized as valid under existing state law prior to becoming part of the Union.