 Where private operation is allowed, for example in horse racing, off-track betting and casinos, the authorities may license only one operator.The early 19th century "Gibbons v. Ogden" case weakened the steamboat monopoly that New York had granted, producing an exception for interstate commerce.However the later Slaughter-House Cases established that a local law creating a legal monopoly did not violate the rights of other merchants in the United States.