what is the function of the secret service
United States Secret Service The United States Secret Service (also USSS or Secret Service) is a federal law enforcement agency under the United States Department of Homeland Security, charged with conducting criminal investigations and protecting the nation's leaders.[2] Until 2003, the Service was part of the U.S. Department of the Treasury, as the agency was originally founded to combat the then-widespread counterfeiting of U.S. currency.[3]