The first rule of logic, Aristotle affirmed, is the law of non-contradiction: A thing cannot be "A" and "not A" at the same time. It's either one or the other.

If politicians would apply this first rule, it would bring us quickly to the last word on the accusation that the administration manipulated intelligence reports prior to invading Iraq to deceive people into falsely believing Saddam Hussein had weapons of mass destruction.

Last week, I wrote that Secretary of State Colin Powell was vindicated by the discovery of two mobile bio-weapons production facilities in Iraq. In his speech to the United Nations on Feb. 5, Powell said Iraq had such facilities. He was right.

But that was not the only unambiguous -- and potentially refutable -- declaration in Powell's speech. He also said that as of Nov. 10, 2002, Iraq had "active chemical munitions bunkers" at a place called Taji, and that these bunkers had been "sanitized" prior to a Dec. 22, 2002, visit by U.N. weapons inspectors.

To prove this, Powell showed two contrasting satellite images of Taji. He explained in detail why the United States knew that the first image, taken Nov. 10, depicted active chemical munitions bunkers. The image, he said, showed two "signature" items for such bunkers -- a security facility to "monitor any leakage" and "a decontamination vehicle in case something goes wrong."

The second image depicted "sanitized bunkers" six weeks later. "The signature vehicles are gone, the tents are gone," said Powell. "It's been cleaned up."

Now, the law of non-contradiction kicks in. As of Nov. 10, these facilities either were, or were not, the active chemical munitions bunkers Powell said they were. Powell was right, or Powell was wrong.

If it turns out Powell was wrong, we face another question: The intelligence analysis backing up his statement about Taji was either mistaken or a lie.

If mistaken, the United States has a serious problem with the quality of its intelligence analysis. If a lie, the administration faces a scandal: Someone took good analysis and distorted it to build a case for war.

But if you listen carefully to Sen. Bob Graham of Florida -- a Democratic presidential candidate who used to serve as Senate Intelligence chairman -- you can make an educated guess about what the truth will turn out to be here.

If Aristotle demonstrated the law of non-contradiction in logic, Graham is demonstrating its inverse corollary in politics: Candidates contradict themselves all the time.

On CNN, June 1, Graham floated the idea that the administration had "manipulated" intelligence of WMD in Iraq. "If they (WMD) are not found," he said, "that will indicate a very serious intelligence failure, or the attempt to keep the American people in the dark by manipulating that intelligence information." But when anchor Wolf Blitzer pushed him for a "bottom-line assessment" of whether there was manipulation, Graham said: "I have seen the same information, or at least most of the same information, that has been made available to the president and his advisers, and it made a compelling case."

I called Graham's office to ask if he had ever questioned the credibility of the analysis Powell had presented at the United Nations about Taji.

"He had no reason to doubt that information at the time," said Paul Anderson, Graham's communications director.

"And no reason to believe that the administration tried to corrupt the analysis in order to present a false picture of that imagery to Congress or the U.N.?" I asked. Continued...