America's long-awaited report into the September 11 attacks was published yesterday with a damning indictment of the system of government, citing "deep institutional failings" in defending the country from attack.
After 20 months of investigations the independent commission blamed the administrations of President George W Bush and his predecessor, Bill Clinton, for failing to combat the danger.
"The most important failure" leading to the attacks was "one of imagination," it concluded. "We do not believe leaders understood the gravity of the threat."
Tom Kean, the chairman of the 9/11 Commission, said: "[They] penetrated the defences of the most powerful nation in the world. They inflicted unbearable trauma on our people, and at the same time they turned the international order upside down."
The al-Qa'eda attacks on New York and Washington killed 3,000 people when four airliners were hijacked and crashed in New York, Washington and Pennsylvania.
It was the worst surprise attack against America since Pearl Harbor in 1941.
But crucially for Mr Bush as he battles for re-election, the 567-page report did not single him out for criticism. It spread the responsibility to Mr Clinton's presidency and savaged Congress for failing in its duty of overseeing the workings of government.
It also delivered another blow to the administration's case for war against Iraq, finding there was no evidence of any "collaborative link" between Iraq and al-Qa'eda, further needling one of Mr Bush's potential weaknesses.
Mr Kean, a Republican, spoke of a failure "of policy management, capability and above all imagination; on that September day we were unprepared. We did not grasp the magnitude of a threat that had been gathering over a considerable period of time."
He conceded that the 10 commissioners had "the benefit of hindsight" that the hijackers "were flexible and resourceful" and it could not be known "whether any single step or series of steps would have defeated them".
But he said none of the counter-terrorism measures adopted before the attacks disturbed or delayed the progress of the al-Qa'eda plot.
On the eve of the report's publication startling video footage surfaced showing four of the 19 hijackers undergoing secondary security checks at Washington's Dulles airport before being allowed to board the plane they were to fly into the Pentagon.
Two were on a terrorist watchlist, but there was no evidence that they were carrying anything that would have led to their being detained.
The report highlights 10 missed opportunities to detect the plot and pre-empt the 19 hijackers, four under Mr Clinton, and six under Mr Bush.
They include specific failings by the immigration authorities, the FBI and the CIA. The report also criticises the State Department and the Pentagon for failing to form a coherent policy against al-Qa'eda.
The principal recommendation was for a centre to unify more than a dozen agencies that gather intelligence at home and abroad and often compete for government resources and attention.
It would be overseen by a cabinet official reporting directly to the president and "would be able to influence the budget and leadership" of the CIA, FBI, Homeland Security Department and Defence Department.
The report did not recommend the creation of a domestic intelligence agency on the lines of MI5, as some in Congress wanted. Instead it endorsed FBI plans to set up its own specialised intelligence service.
Mr Bush, who took office eight months before the attacks, bitterly opposed the creation of the commission.
His aides feared the political impact of the report in the light of testimony to the commission in the past few months that showed he received dire warnings about al-Qa'eda before the attacks.
The report said that despite many warnings only a week before the attacks on the World Trade Centre and the Pentagon the Bush administration had not decided whether al-Qa'eda was a "big deal."
But, to the frustration of many Democrats, the commission avoided making any points that could be perceived as political. National security, until recently Mr Bush's strongest political suit, has emerged as the key issue in the November elections.
As Mr Bush received a copy of the report at the White House, he thanked the commissioners and said they made "very solid, sound recommendations about how to move forward".
He said he had assured them "that where the government needs to act we will".
Senator John Kerry, his Democratic challenger who is slightly ahead in many polls, said: "This report carries a simple message for all of America, about the security of all Americans: We can do better. We must do better and there is an urgency about us doing better."
If elected he would immediately convene an emergency security summit, bringing leading Democrats and Republicans together to reform security agencies.
"The terrorists will not wait for us and we will not wait for them," he said.
