Failing to foresee the cataclysmic events of Sept. 11, it has been said, was not so much a failure of intelligence as a failure of imagination. The government, we have been told, could not have predicted, much less prevented, the evil and chaos unleashed that day.

Yet it turns out that President Bush was warned by U.S. intelligence agencies in early August that Osama bin Laden's terrorist network was plotting airplane hijackings. Even with that information, according to the administration, no one contemplated that hijackers might turn airplanes into suicide bombs.

This has prompted a blizzard of questions. If Bush knew something, why did he keep it secret from the public? How many warnings were there? Why weren't they connected?

This does have to be considered in the context of life before Sept. 11. The mosaic of intelligence gathered daily by the CIA and other national security agencies is enormous. The threats uncovered before Sept. 11 are said to have been non-specific as to time and place.

One thing, though, should be abundantly clear: The public can and should be trusted with information, including information that might be alarming. The warnings of terrorist plots timed to the Millennium celebrations are a case in point. People were told of the possibility, no one panicked, security was tightened. At least one apparent plot was stopped.

When information is held secret, it breeds suspicion. Conspiracy theories about Sept. 11 have abounded for months, fed most prominently by Rep. Cynthia McKinney, (D-Ga.), who has suggested that Bush may have known about the looming attacks and permitted them to happen because friends in the defense industry stood to gain from the ensuing war.

This line of thinking is nothing new. Franklin D. Roosevelt was accused of knowing about Pearl Harbor in advance and doing nothing because he wanted an excuse to draw the U.S. into World War II. Similar theories have surrounded the sinking of the Lusitania in 1915 and U.S. entry into World War I.

The conspiracy theories around Sept. 11 have no more credence than those that have lasted from Pearl Harbor and the Lusitania. The point is that knowledge can flush suspicion away. Secrecy, as should be very apparent in this case, can breed it.

On Thursday, official Washington was looking for someone to blame and the conspiracy theorists were puffing up for a collective, "told you so."

It is important to create as clear and full a record of the events before and after Sept. 11 as is possible. Congress should probe the intelligence gathering and dissemination processósomething it is already doing. It is crucial to know just what information was available, and how it was disseminated within the CIA, FBI and other agencies. For example, what, if anything, was done after a remarkably prescient FBI agent in Phoenix urged headquarters to investigate men from the Mideast who were enrolling in U.S. flight schools?

In many respects the government has started to address these issues. Homeland Security Director Tom Ridge created a terrorism warning system. We've gotten used to that system, but it is far from perfect. There is still no clear protocol on how and when the public will be told of specific threats.

The finger-pointing will go on for some time, but the overall message to government should be clear: Trust us, tell us, lest you forfeit our trust.