The USA PATRIOT Act became law on October 26, 2001, six weeks after the September 11 attacks. Senator Patrick Leahy later recalled that he and House Majority Leader Dick Armey “insisted that we add a sunset for certain governmental powers.” Those provisions would expire at the end of 2005 unless Congress renewed them.
Leahy said the sunset “ensured that we would revisit the PATRIOT Act.” In March 2006, Congress made 14 of the 16 expiring provisions permanent. The other two received new sunsets of four years.