United States Secret Service
The United States Secret Service was set up by the Treasury Department in 1865, as an investigative agency working financial crimes. But after the assassination of President William McKinley in 1901, the Secret Service was brought in to function, in effect, as the presidents official body guard. Now under the umbrella of the Department of Homeland Security, the ranks of the Secret Service include thousands of uniformed and under cover agents, all tasked with keeping the president secure from outside threats.
The Secret Service is a United States federal government law enforcement agency that is most known for presidential protection duties. Although it previously operated within the Department of the Treasury, in 2003 the Secret Service was transferred to the newly-formed Department of Homeland Security.
The Secret Service's current primary investigative mission is to safeguard the payment and financial systems of the United States. This has been historically accomplished through the enforcement of the counterfeiting statutes to preserve the integrity of United States currency, coin and financial obligations. Since 1984, its investigative responsibilities have expanded to include crimes that involve financial institution fraud, computer and telecommunications fraud, false identification documents, access device fraud, advance fee fraud, electronic funds transfers, and money laundering as it relates to core violations.
It of course, is most known for the protection of the President, Vice President, their immediate families, other high ranking government officials, past presidents and their spouses, certain candidates for the offices of President and Vice President, and visiting foreign heads of state and government (all called "protectees").
The Secret Service was established as a law enforcement agency in 1865. While most people associate the Secret Service with Presidential protection, its original mandate was to investigate the counterfeiting of U.S. currency, a job it still performs. William P. Wood was the first Chief of the U.S. Secret Service. In 1867, Secret Service responsibilities were broadened to include "detecting persons perpetrating frauds against the government." This appropriation resulted in investigations into the Ku Klux Klan, non-conforming distillers, smugglers, mail robbers, land frauds, and a number of other infractions against the federal laws.
In 1901, Congress informally requested Secret Service Presidential protection following the assassination of President William McKinley. The Secret Service assumed full-time responsibility for protection of the President in 1902, and two operatives were assigned full time to the White House Detail. President Roosevelt transferred eight Secret Service agents to the Department of Justice, which formed the nucleus of what is now the Federal Bureau of Investigation (FBI). Triggered by the attack on President Harry Truman, Congress enacted legislation that permanently authorized Secret Service protection of the President, his immediate family, the President-elect, and the Vice President (or the next officer to succeed the President) and the Vice President-elect.
In 1965, Congress authorized the Secret Service to protect former Presidents and their spouses during their lifetime and minor children until age 16. As a result of Robert F. Kennedy's assassination, Congress authorized protection of major Presidential and Vice Presidential candidates and nominees, as well as their spouses, within 120 days of a general Presidential election. Congress also authorized protection of widows of Presidents until death, or remarriage, and their children until age 16.