A new report from the chief U.S. weapon “hunter” in Iraq confirms what has been known for months: Iraq had no weapons of mass destruction when invaded by the United States.

This is an important finding, if only because President Bush made the presence of such weapons the foundation for his decision to go to war against Iraq.

“Saddam Hussein is a man who told the world he wouldn’t have weapons of mass destruction, but he’s got them,” Bush said on Nov. 3, 2002.

He and Vice President Dick Cheney flatly asserted in the months leading up to the war that Hussein had chemical and biological weapons and that he was pursuing efforts to acquire nuclear weapons.

“Simply stated, there is no doubt that Saddam Hussein now has weapons of mass destruction. There is no doubt he is amassing them to use against our friends, against our allies, and against us,” Cheney said on Aug. 26, 2002.

On Thursday, in the wake of the release of a report the chief U.S. weapons hunter, Charles Duelfer, President Bush finally acknowledged that this was not true.

“Iraq did not have the weapons that our intelligence believed were there,” Bush, according to the AP, told reporters.

But Bush and Cheney also noted that Duelfer believed that Hussein intended to reconstitute programs to develop nuclear and other weapons once U.N. sanctions had been removed.

“The Duelfer report showed that Saddam was systematically gaming the system, using the U.N. oil-for-food program to try to influence countries and companies in an effort to undermine sanctions,” Bush said. “He was doing so with the intent of restarting his weapons program once the world looked away.”

This line of defense about the justification for the war brought a blistering — and warranted — response from Democratic presidential nominee John Kerry: “You don’t make up or find reasons to go to war after the fact.”

It’s certain that Bush and Kerry will argue the merits of the decision to attack Iraq throughout the remainder of the campaign. And it’s certain the debate will play out in black and white terms, Kerry arguing that Bush was wrong, Bush asserting his decision was the right one.

But as Duelfer and others who have had the opportunity to sort through the mists have shown, simplistic bombast can’t explain what was actually going on in Iraq at the time.

Saddam Hussein had indeed had weapons of mass destruction at one time, but by the available evidence had gotten rid of most of them following the first Gulf War — though he refused to account for them to U.N. inspectors. He had a motive for wanting such weapons — though it was apparently driven more by fear of his neighbors than it was an intention to use them against the United States. And Duelfer himself surmised that Hussein wanted eventually to resurrect his weapons programs.

It bears noting that Bush, in his remarks Thursday, suggested that he was relying on what “our intelligence” was reporting.

But the buck stops at his desk. And the overriding fact is that the Bush administration was wrong. Saddam Hussein never had the weapons of massage destruction that Bush said he had.