Within months of the creation of the Office of Homeland Security, Republicans in Congress in January 2002 introduced the Homeland Security Act. The House and Senate approved the statute in November 2002, and Bush signed the bill into law that month. The statute called for the largest restructuring of federal administrative agencies since the creation of the Department of Defense in 1947. The act created the Department of Homeland Security as a cabinet-level department, under which more than 20 existing agencies would merge.
The president nominates a secretary to lead the department. The Senate must approve the nominee. Bush appointed Ridge to be the secretary of this new department, and Ridge served in this capacity until 2005. On February 15, 2005, Michael Chertoff, a former federal judge in the Third Circuit Court of Appeals, was sworn in as secretary, replacing Ridge.