In the largest government overhaul since the Defense Department was created in 1947, Washington revamped its security agencies after the 9/11 attacks. Security spending also surged, from $16.8 billion in 2001 to $55 billion this year. A look at some of the changes:

HOMELAND SECURITY DEPARTMENT

Twenty-two disparate agencies and 180,000 employees, including FEMA and the Secret Service, were merged under one roof in March 2003. The department oversees security operations at ports, on airlines and at U.S. borders. It is in charge of the nation's color-coded threat assessment for terrorism. Homeland Security also is the federal point of contact for state and local civilian authorities seeking intelligence or other classified information about threats. Though it was created in response to 9/11, the department shifted its focus from terrorism to "all hazards" shortly before Hurricane Katrina hit the Gulf Coast last year.

TRANSPORTATION SECURITY ADMINISTRATION

Congress rushed TSA into existence weeks after 9/11 as part of the Transportation Department. It moved into Homeland Security in March 2003. Though TSA was supposed to protect all modes of transportation, Congress gave it a list of tasks and deadlines aimed almost exclusively at preventing terrorist attacks on passenger airlines. Thousands of undercover air marshals were hired, trained and deployed aboard commercial flights. More than 50,000 security screeners were hired and trained to take over airport security from contractors employed by airlines. Billions of dollars were spent on installing bomb detection machines at airports to scan every piece of checked baggage for traces of explosives.

JUSTICE DEPARTMENT/FBI

The top priority at the FBI changed from fighting crime to preventing terrorism. Hundreds of intelligence analysts were hired and assigned to FBI field offices, while hundreds of agents were shifted to counterterrorism cases from traditional jobs investigating bank robberies and other crimes. Additionally, the USA Patriot Act, enacted 45 days after the attacks, lowered the wall between intelligence and law enforcement, and relaxed standards for surreptitious surveillance in counterterrorism investigations.

INTELLIGENCE