Both the Bush administration and the Clinton White House before it were well aware of the growing threat that al-Qaida posed to the United States. As far back as 1993, the group was implicated in the first terrorist attack on the World Trade Center. What this commission is now trying to determine is whether either administration could have done more to head off the 9/11 attacks, including taking more aggressive military action against Osama bin-Laden's group.

President Bush says he would have taken swift action if he had information that an attack on the United States was imminent. His administration did not complete a review of its counter terrorism policy until the same month as the 9/11 attacks that claimed some three thousand lives.

But in sworn testimony -- and with relatives of some of those who died on that day present -- Defense Secretary Donald Rumsfeld told the panel, "I knew of no intelligence during the six plus months leading up to September 11th that indicated terrorists would hijack commercial airliners, use them as missiles to fly into the Pentagon or the World Trade Center towers."

But Commissioner Bob Kerrey challenged that the incoming Bush administration -aware that the United States had already been hit multiple times by al-Qaida terrorists- should have declared war on the group prior to being hit again September 11.

"This was an army led by Osama bin-Laden who declared war on us on February 23, 1998 and we had all kinds of reasons, I've heard them all, and they're all wonderful, as to why the only military attack we had was a single attack on the August 20, 1998 and other than that, there wasn't anything," said Mr. Kerrey. "And 19 men as a consequence, defeated us utterly with less than a half a million dollars."

As to a declaration of war, Defense Secretary Rumsfeld responded, "I don't think it would have stopped September 11."

Secretary of State Colin Powell told the commission much the same. "Invading Afghanistan and cutting off the head, if you succeeded in getting Osama bin-Laden and disrupting al-Qaida at that point, I have no reason to believe that would have caused them to abort their plans," he says.

Earlier, his predecessor as Secretary of State, Madeleine Albright told the commission the Clinton administration did go on the offensive against al-Qaida after they bombed two American embassies in Africa in 1998. "In subsequent weeks, the president specifically authorized the use of force and there should have been no confusion that our personnel were authorized to kill bin-Laden," she says.

U.S. cruise missiles did strike at Al-Qaida training camps in Afghanistan and a pharmaceutical factory in Sudan but the bin-Laden network continued to carry out more terrorist attacks.

The 9/11 commission was created two years ago over the initial objections of the White House. The Bush administration has upset some members including Tim Roemer, because of the refusal of National Security Advisor Condoleezza Rice to testify in open session.

"I hope Dr. Rice will reconsider and come before our commission for the sake of the American people tomorrow," he said. She has given a private interview to several members of the panel.

These hearings come amid a heated election year debate in Washington triggered by a new book by former top government counterterrorism official Richard Clarke. He alleges the Bush administration, despite spending millions of dollars on intelligence, ignored warnings about the threat posed by al-Qaida and instead shifted its focus to Iraq.

By the time it completes its work - expected by late July -- the panel will have interviewed more than a thousand people in 10 different countries, and reviewed millions of pages of documents.