The London Packet was a case heard by the US Supreme Court in 1817. The claimant, Merino, argued that he had been wrongfully denied payment for goods shipped to him on board the vessel "London Packet". He claimed that his contract with the ship's captain entitled him to receive payment upon delivery of his goods and requested damages from the defendants for their failure to pay. The court found in favor of Merino and held that when a shipper contracts with a carrier for delivery of goods, it is implied that they will be paid upon arrival at their destination. Furthermore, if there is any breach or non-performance of this agreement then damages may be awarded as compensation. This ruling established an important precedent regarding contractual obligations between carriers and shippers which has since become part of maritime law today.

The London Packet, Merino, Claimant case was a dispute between the United States and Great Britain over a ship that had been seized by British forces during the War of 1812. The Supreme Court held that under international law, the seizure of neutral vessels is only lawful when they are carrying contraband or enemy property. In this case, there was no evidence to suggest either condition applied to The London Packet so it should have been returned to its rightful owner upon conclusion of hostilities. Justice Johnson wrote in his dissenting opinion that he believed Congress had authorized such seizures as part of their war powers and thus were valid even if not supported by international law. He argued further that since Congress has exclusive power over foreign affairs then any action taken pursuant thereto must be respected regardless whether it violated customary principles governing maritime warfare at the time or not.