Secret Service executives implement an “emergency call-up” of all their agency’s personnel at some time after 9:37 a.m., when the Pentagon was hit, according to US News and World Report. The reason why the Secret Service did not call up all its personnel earlier on is unstated, as is the reason it decides to do so now. [US News and World Report, 12/1/2002] The Secret Service is responsible for protecting the nation’s “most visible targets,” including the president, the vice president, and the White House complex. [US Department of the Treasury, 5/8/2001; Office of Management and Budget, 7/2001, pp. 82 ] Brian Stafford, the agency’s director, realized the US was under attack after the second plane hit the World Trade Center at 9:03 a.m. (see 9:03 a.m. September 11, 2001), and then activated the Director’s Crisis Center at Secret Service headquarters to manage the agency’s response (see (Shortly After 9:03 a.m.) September 11, 2001). [United States Secret Service, 10/1/2001; Peter Schnall, 10/24/2004] And since around 9:18 a.m., a meeting has been taking place in the office of Carl Truscott, the special agent in charge of the presidential protective division, during which Truscott and three other senior Secret Service agents have discussed security enhancements at the White House (see (9:18 a.m.) September 11, 2001). [United States Secret Service, 10/1/2001]