United States Secret Service

The United States Secret Service is a federal law enforcement agency under the Department of Homeland Security with the purpose of conducting criminal investigations and protecting U.S. political leaders, their families, and visiting heads of state or government. The Secret Service was, until 2003, part of the Department of the Treasury, due to their initial mandate of combatting counterfeiting of U.S. currency. The agency has protected U.S. presidents and presidential candidates since 1901.