Tenet said it is true that U.S. intelligence knew about Osama bin Laden's intention to hit America. But, Tenet said, the CIA and other intelligence agencies were unable to translate this knowledge into preventing the 11 September attacks.
"Warning is not good enough without the structure to put it into action. We all understood bin Laden's attempt to strike the homeland, but we never translated this knowledge into an effective defense of the country. Doing so would have complicated the terrorists' calculation of the difficulty in succeeding in a vast, open society that, in effect, was unprotected on 11 September," Tenet said.
The commission's staff released a preliminary report on 13 April that said U.S. intelligence missed what it called the big-picture significance of telltale indicators of impending terrorist attacks. The report said a more strategic analysis could have identified the plot of the suicide hijackers.
The attacks on New York and the Pentagon were carried out by militant Muslims using hijacked jetliners.
The commission's staff report noted that the United States allocates more money to intelligence than most nations spend on national security as a whole. It said most of these funds are spent on intelligence gathering, much of it on very expensive hardware such as systems based in space. The specific amount of money allocated to various programs are classified.
In his testimony, Tenet sought to vigorously defend the CIA while acknowledging some shortcomings: "The intelligence that we provided our senior policy makers about the threat Al-Qaeda posed, its leadership and its operational span across over 60 countries, and the use of Afghanistan as a sanctuary was clear and direct. Warning was well understood, even if the timing and method of attacks were not."
Tenet added: "While we positioned ourselves very well, with extensive human and technical penetrations, to facilitate the take-down of the Afghan sanctuary [for Al-Qaeda], we did not discern the specific nature of the [11 September] plot. We made mistakes."
But Tenet said U.S. intelligence was hampered by the lack of funds and other resources prior to the attacks. For example, Tenet said that by the mid-1990s, the U.S. intelligence community was operating with significant erosion in resources and people and was unable to keep up with technological change.
The CIA chief said that when he took office, U.S. intelligence lost close to 25 percent of its people and billions of dollars in capital investment.
And, Tenet said, there was a wider problem that he could not possibly remedy himself: "All of us took little action to create a common arena of criminal and intelligence data that we could all access. Most profoundly, we lacked a government-wide capability to integrate foreign and domestic knowledge, data operations, and analysis."
Tenet, who has served both U.S. Presidents Bill Clinton and George W. Bush, was praised by several commissioners for his foresight and efforts to restructure intelligence-gathering. Yet the panel's staff report was sharply critical of the agency and apparatus he has lead for seven years as the United States' director of central intelligence.
In addressing the report, Tenet said he had "issues" with several of its conclusions.
The report said that while it is now known that Al-Qaeda was formed in 1988, at the end of the Soviet occupation of Afghanistan, the intelligence community did not describe this organization, at least in the documents it has seen, until 1999.
As late as 1997, the report said, the CIA Counterterrorism Center characterized bin Laden merely as "a financier of terrorism."