Slowly but inexorably, as more and more information emerges, the conventional wisdom about the events leading to war in Iraq is shifting. The American public has joined the rest of the civilized world in questioning the arguments and motives of the war makers. Commentators who have habitually fashioned excuses for the White House seem to find that task increasingly burdensome and humiliating. The old lies no longer have much traction.

Yet even now, President Bush persists in blatantly falsifying the war’s origins — perhaps because, even now, he still gets away with it.

At his most recent press conference, that strange impulse to utter a ridiculous lie seemed to seize the president. It happened when he called on Hearst columnist Helen Thomas.

“I’d like to ask you, Mr. President, your decision to invade Iraq has caused the deaths of thousands of Americans and Iraqis, wounds of Americans and Iraqis for a lifetime,” said the venerable correspondent in her confrontational style. “Every reason given, publicly at least, has turned out not to be true. My question is, why did you really want to go to war?”

Bush responded by denying that he wanted war, a pro forma assertion that nobody believes. He blathered on for a while about Sept. 11, the Taliban, al-Qaida and protecting America from terrorism.

And when Thomas reminded him that she had asked about Iraq, he said, “I also saw a threat in Iraq. I was hoping to solve this problem diplomatically. That’s why I went to the [United Nations] Security Council; that’s why it was important to pass [Resolution] 1441, which was unanimously passed. And the world said, disarm, disclose, or face serious consequences — and therefore, we worked with the world, we worked to make sure that Saddam Hussein heard the message of the world. And when he chose to deny inspectors, when he chose not to disclose [emphasis added], then I had the difficult decision to make to remove him. And we did, and the world is safer for it.”

The official transcript notes “laughter” at that moment.

What was so funny? Were her colleagues laughing at Thomas, whose monopoly on testicular fortitude has shamed them all for so long? In the days that followed, the bully boys of the right-wing media enthusiastically abused Thomas, which was predictable enough. But have the rest of the reporters in the press room become so accustomed to presidential prevarication that they literally cannot hear a stunning falsehood that is repeated over and over again?

For the third time since the war began three years ago, Bush had falsely claimed that Saddam refused the U.N. weapons inspections mandated by the Security Council. For the third time, he had denied a reality witnessed by the entire world during the four months when those inspectors, under the direction of Hans Blix, traveled Iraq searching fruitlessly for weapons of mass destruction that, as we now know for certain, were not there.

But forget about whether the weapons were there for a moment. The inspectors definitely went to Iraq. They left only because the United States warned them to get out before the bombs started to fall on March 19, 2003. But for some reason the president of the United States keeps saying — in public and on the record — that the inspectors weren’t there.

Keeping the facts segregated from the myriad falsehoods isn’t easy with this regime, so let’s review the two previous occasions when Bush made that startling claim.

The first incident was on July 14, 2003, at a White House press conference with U.N. Secretary-General Kofi Annan, who diplomatically declined to contradict him. At that time, the Bush administration was reeling from the impact of former Ambassador Joseph Wilson’s Op-Ed essay about the Niger uranium fiasco in the New York Times, which had appeared a few days earlier.