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.
Foreign policy of the Bill Clinton administration
On February 26, 1993, thirty-six days after Clinton took office, terrorists who the CIA would later reveal were working under the direction of Osama bin Laden detonated a timed car bomb in the parking garage below Tower One of the World Trade Center in New York City (see the World Trade Center bombing). Clinton responded by ordering his National Security Council, under the direction of Anthony Lake, and the FBI to find and punish those responsible. The FBI was able to quickly identify the vehicle used in the bomb from a remnant found in the rubble: a Ryder rental van, which had been reported stolen in Jersey City, New Jersey the day before. The truck was rented by Mohammed Salameh, whom the FBI immediately detained. Similar evidence led to the arrests of other plotters behind the attack, including Nidal Ayyad, Mahmoud Abouhalima, Ahmad Ajaj, and Ramzi Yousef—who was identified as the key player in the bombing. All men were tried and convicted for the bombing and other terrorists activities.