The agency's mission has evolved dramatically since its inception under the Treasury Department. Today, there are more than 3,200 members, ready to sacrifice their lives for he safety of the leader of the free world.
The agency's job originally was to stamp out counterfeiting in an era when one out of every three bills in circulation was fake. Presidential security became a formal objective after the assassination of President McKinley in 1901. It wasn't until 1951, after a failed attempt on President Truman, that Congress codified the agency's permanent protection of the First Family. Its duties also now include candidates for high office (they have been guarding "Renegade" since May 2007, longer than any other presidential candidate in U.S. history).
Monitoring for fiscal malfeasance is still half of the agency's job though. In August, the Secret Service helped crack what was heralded as the largest identity-theft ring in U.S. history (so where was the publicity on this? Oh, thats right, our media machine usually only reports on the negative. End of Rant :o).
Hope you enjoyed this little historical stroll :o)