The Homeland Security Act (HSA) of 2002, (Pub. L. 107–296, 116 Stat. 2135, enacted November 25, 2002) was introduced in the aftermath of the September 11 attacks and subsequent mailings of anthrax spores.  The HSA was cosponsored by 118 members of Congress.  It was signed into law by President George W. Bush in November 2002. 
HSA created the United States Department of Homeland Security and the new cabinet-level position of Secretary of Homeland Security. It is the largest federal government reorganization since the Department of Defense was created via the National Security Act of 1947 (as amended in 1949). It also includes many of the organizations under which the powers of the USA PATRIOT Act are exercised.