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The are a snapshot in time. They came at the conclusion of the joint House-Senate Intelligence Committees' inquiry and before the started its work in 2003. Those pages and many others previously released posed questions for further investigation, based on the committees’ review of raw intelligence and FBI reports. The 9/11 Commission took the baton and followed up on most of those leads, but not all.

Among those dangling strands of the investigation, two stand out. The first, the subject of these 28 pages, is what role Saudi government officials played in supporting al-Qaeda and the 9/11 plot.

The second question, with which the 9/11 Commission struggled but was unable to answer, is why the CIA failed to tell the FBI and the White House when the agency knew about al-Qaeda terrorists in the United States.

I believe that the two questions may be linked and that a major element of the 9/11 tragedy may remain unrevealed: a possible failed CIA-Saudi spy mission on U.S. soil that went bad and eventually allowed 9/11 to proceed unimpeded.

My perspective on these issues is shaped by my job in the Clinton and Bush administrations, the national coordinator for counterterrorism, based in the White House’s National Security Council. In that role, I was constantly reading detailed intelligence reports and being briefed by the CIA, the FBI and other agencies concerning possible terrorist plots.