United States Secret Service
The United States Secret Service (USSS) is a federal law enforcement agency under the U.S. Department of Homeland Security. Until 2003, the Service was part of the U.S. Department of the Treasury.The U.S. Secret Service has two distinct areas of responsibility: Financial Crimes, covering missions such as prevention and investigation of counterfeit U.S. currency, U.S. treasury securities, and investigation of major fraud. Protection, which entails ensuring the safety of current and former national leaders and their families, such as the President, past Presidents, Vice Presidents, presidential candidates, visiting heads of state, and foreign embassies.The Secret Service's initial responsibility was to investigate counterfeiting of U.S. currency, which was rampant following the U.S. Civil War. The agency then evolved into the United States' first domestic intelligence and counterintelligence agency. Many of the agency's missions were later taken over by subsequent agencies such as the Federal Bureau of Investigation (FBI), Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), and Internal Revenue Service (IRS).