The resumed hearings and preliminary staff reports of the September 11 commission are producing some shocking, hitherto not public, information regarding the 2001 attacks.

The information is also undercutting a key theme and repeated message of President George W. Bush and Vice President Dick Cheney -- that there was cooperation between al-Qaida, which carried out the Sept. 11 attacks, and Saddam Hussein's Iraq.

This claim of an al-Qaida-Iraq link has been used by the Bush administration as critical underpinning in its argument that the United States had to go to war with Iraq. If the information the commission has put together is correct -- and it seems to be very sound -- then the claim of Mr. Bush and Mr. Cheney is either a persistent misunderstanding on their part, or, as some believe, a big lie.

The "big lie" theory is that the Iraq-al-Qaida link is so critical to the administration's case for the war that it cannot afford to relinquish it. It is thus continuing to repeat it, hoping that American voters will buy it through the elections in the fall.

As recently as Monday, Mr. Cheney told an audience at the James Madison Institute in Orlando, Fla., that Saddam Hussein "... had long-established ties with al-Qaida." Mr. Bush himself took issue with the commission's assessment yesterday. Other disturbing information that is emerging through the commission's work includes the fact that al-Qaida's original plan for a U.S. attack was much more ambitious than what was actually carried out Sept. 11. California and Washington State targets as well as the World Trade Center, the White House, the Capitol and the Pentagon were under serious consideration for attacks. Preparations had begun as early as 1999, which raises the question of how they could have proceeded for so long without the CIA and the FBI somehow stumbling upon them.

Yesterday's hearings also revealed that the preparedness and reaction of the Federal Aviation Administration and the United States Air Force on Sept. 11 were less than sterling.

It is, of course, always difficult to judge the quality of the information that the commission is using as the basis of its conclusions. One flaw is coming to be endemic to Bush administration practice: It appears that two key sources, senior al-Qaida officials Khalid Shaikh Mohammed and Ramzi bin al-Shibh, may have been tortured to obtain the information they provided. The administration denies it.

A second problem, one that always exists with the CIA and the FBI, is that a commission that receives information from those agencies never knows what they have omitted from their reports.

All of that said, the information that the commission is putting together and making available to the public is definitely worth examination. Its final report, due next month, will command close study not only on how 9/11 unfolded but also on how the United States should protect itself in the future.