Donald Rumsfeld
The United States was attacked on September 11, 2001 by al Qaeda terrorists who hijacked commercial airliners and crashed them in coordinated strikes into both towers of the World Trade Center in Lower Manhattan, New York City and the Pentagon in Washington, D.C. The fourth plane crashed into a field in Shanksville, Pennsylvania, and its target was likely a prominent building in Washington, D.C., most probably either the Capitol Building or the White House. Within three hours of the start of the first hijacking and two hours after American Airlines Flight 11 struck the World Trade Center, Rumsfeld raised the defense condition signaling of the United States offensive readiness to DEFCON 3, the highest it had been since the Arab-Israeli war in 1973.
International counter-terrorism activities of the CIA
On February 26, 1993, the World Trade Center was bombed. A group of the conspirators were arrested, convicted, and imprisoned. There has been no strong argument that al-Qaeda was involved, although there have been allegations, including by a former Director of Central Intelligence, that Iraq supported the operational cell. In a PBS interview in October 2001, former Clinton-era CIA Director James Woolsey argued a supposed link between Ramzi Youssef and the Iraqi intelligence services. He suggested the grand jury investigation turned up evidence pointing to Iraq that the Clinton Justice Department "brushed aside."