Stanley v. Colt was a United States Supreme Court case that was decided in 1866. The case involved a dispute between two parties over a contract for the sale of a steamboat. The plaintiff, Stanley, had contracted with the defendant, Colt, to purchase a steamboat for $2,000. Stanley paid Colt the full amount, but Colt failed to deliver the boat. Stanley then sued Colt for breach of contract. The Supreme Court held that Colt was liable for breach of contract. The Court found that Colt had failed to fulfill his contractual obligations and that Stanley was entitled to damages. The Court also held that Stanley was entitled to recover the full amount of the purchase price, plus interest. The Court's decision in Stanley v. Colt established the principle that a party who breaches a contract is liable for damages. This decision has been cited in numerous subsequent cases and is still used today to determine the rights and obligations of parties in contract disputes.

In the case of Stanley v. Colt, the Supreme Court was asked to decide whether a contract between two parties could be enforced when it had been made in violation of an existing state law. The majority opinion held that contracts which violated state laws were not enforceable and thus granted judgment for the defendant. However, Justice Field dissented from this ruling on the basis that such a decision would lead to unjust results and create uncertainty in contractual relations between individuals. He argued that if courts refused to enforce contracts simply because they violated some statute or regulation then no one would know what obligations they might have under any given agreement since those obligations could change at any time depending upon new legislation or regulations passed by states or other governmental bodies. Furthermore, he asserted that enforcing such agreements did not necessarily mean condoning their illegality but rather recognizing them as valid until declared otherwise by competent authority with jurisdiction over them.