He announced a new doctrine of pre-emptive strikes against those states considered to be a threat. He deployed the power of the US military in combat and the pressure of US diplomacy in persuasion. At home, a thousand or more people, mainly foreigners, were rounded up on immigration charges or held as “material witnesses” as information was desperately sought.
Several hundred captured suspects from al-Qaeda and the Taleban were held at the US base in Guantanamo Bay. Military tribunals were authorised. There was anger in Congress at the failure of the FBI and the CIA to “join up the dots” in intelligence before 11 September and reforms were ordered in both agencies.
Mr Bush proposed a new cabinet-level department of Homeland Security to combine the duties of 22 government bodies. Public concern was further raised with the arrest of Jose Padilla, also known as Abdullah al-Muhajir, suspected of trying to make a radiation or “dirty bomb”. The United States prepared for a long and new kind of warfare.
BBC News Online's World Affairs correspondent Paul Reynolds outlines why the suicide hijacks had such a profound effect on America.
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