Washington ? Contradicting the main argument for a war that has cost more than 1,000 American lives, the top U.S. arms inspector said Wednesday he found no evidence that Iraq produced weapons of mass destruction after 1991. He also concluded that Saddam Hussein’s ability to develop such weapons had dimmed — not grown — during a dozen years of sanctions before last year’s U.S. invasion.

Contrary to prewar statements by President Bush, Saddam did not have chemical and biological stockpiles when the war began and his nuclear capabilities were deteriorating, not advancing, said Charles Duelfer, head of the Iraq Survey Group.

The findings, which contradict nearly every prewar assertion made by top administration officials about Iraq, come less than four weeks before an election in which Bush’s handling of Iraq is the central issue. They could boost Democratic candidate John Kerry’s contention that Bush rushed to war based on faulty intelligence and that United Nations sanctions and weapons inspectors should have been given more time.

But Duelfer also supports Bush’s argument that Saddam remained a threat. Interviews with the toppled leader and other former Iraqi officials made clear that Saddam still wanted to pursue weapons of mass destruction and hoped to revive his weapons program if U.N. sanctions were lifted.

“What is clear is that Saddam retained his notions of use of force and had experiences that demonstrated the utility of WMD,” Duelfer told Congress.

Fodder for campaign

Campaigning in Pennsylvania, Bush defended the decision to invade.

“There was a risk, a real risk, that Saddam Hussein would pass weapons or materials or information to terrorist networks,” Bush said in a speech in Wilkes Barre, Pa. “In the world after Sept. 11, that was a risk we could not afford to take.”

But Democratic vice presidential candidate John Edwards, campaigning in West Palm Beach, Fla., said Bush and Vice President Dick Cheney “are in a complete state of denial” about the war.

Sen. Carl Levin of Michigan, the top Democrat on the Armed Services Committee, said Duelfer’s findings undercut the administration’s argument for war. “We did not go to war because Saddam had future intentions to obtain weapons of mass destruction,” Levin said.

The report also concludes that the Iraqi government was able to manipulate a U.N. oil-for-food program to avoid the sanctions’ effects for a few years, acquiring billions of dollars to import goods such as parts for missile systems. Duelfer also in the report accused the former head of the U.N. oil-for-food program of accepting bribes in the form of vouchers for Iraqi oil sales from Saddam’s government.

“Once the oil-for-food program began, it provided all kind of levers for him (Saddam) to manipulate his way out of sanctions,” Duelfer told Congress on Wednesday.

Duelfer said sanctions against Saddam — even though they appeared to work in part — were unsustainable long term.

Point by point

Based on 16 months’ work, the report vastly expands on previous efforts by U.N. inspectors and Duelfer’s predecessor, David Kay.

On specific points, Duelfer said:

l He concluded that aluminum tubes suspected of being used for enriching uranium for use in a nuclear bomb were likely destined for conventional rockets and there was no evidence Iraq sought uranium abroad after 1991. Both findings contradict claims made by Bush and other top administration officials before the war.

l It was unclear what happened to banned weapons produced before 1991 that Saddam had declared in the 1990s to the United Nations but were never accounted for. For example, Saddam declared having 550 155-millimeter artillery shells with mustard agents, but it’s not known what became of most of them. Duelfer said 53 “residual rounds” have been found and the others were not considered a significant threat.

l The likelihood of finding the stockpiles that the president spoke about before the war was “less than 5 percent.”

l The inspectors found no evidence that Saddam was passing weapons of mass destruction material to terrorist groups but Duelfer added that wasn’t a strong focus of his report.

Traveling in Africa, British Prime Minister Tony Blair, Bush’s main foreign ally in the war, said the report showed Saddam was “doing his best” to evade the U.N. sanctions.

But the former head of the U.N. weapons inspection team, Hans Blix, said: “Had we had a few months more (of inspections before the war), we would have been able to tell both the CIA and others that there were no weapons of mass destruction (at) all the sites that they had given to us.”

Prewar claims

The report avoids direct comparisons with prewar claims by the Bush administration on Iraq’s weapons systems. But Duelfer largely reinforces the conclusions of Kay, his predecessor, who said in January, “We were almost all wrong” on Saddam’s weapons programs. Duelfer said the same words Wednesday to a Senate panel.

He found that Saddam, hoping to end U.N. sanctions, gradually began ending prohibited weapons programs starting in 1991. But as Iraq started receiving money through the U.N. oil-for-food program, and as enforcement of the sanctions weakened, Saddam was able to take steps to rebuild his military, such as acquiring parts for missile systems.

However, the erosion of sanctions stopped after the Sept. 11, 2001, attacks, Duelfer found, preventing Saddam from pursuing weapons of mass destruction.

After Sept. 11, he said, Iraq was more isolated diplomatically, U.S. forces were gathering on the border, Iraq’s revenues were dropping and it was forced to let inspectors in. But Duelfer said it was unlikely that level of pressure could have been sustained because of the costs both for the United States and for Iraqis.

His team found no written plans by Saddam’s regime to pursue banned weapons if U.N. sanctions were lifted. Instead, the inspectors based their findings on interviews with Saddam after his capture, as well as talks with other top Iraqi officials.

The inspectors found Saddam was particularly concerned about the threat posed by Iran, the country’s enemy in a 1980-88 war. Saddam said he would meet Iran’s threat by any means necessary, which Duelfer understood to mean weapons of mass destruction.

Duelfer concluded Saddam was not motivated by a desire to strike the United States with banned weapons, but wanted them to enhance his image in the Middle East and to deter Iran. Saddam believed “WMD helped save the regime multiple times,” the report said.

Saddam also believed his use of chemical weapons against Iran had prevented Iraq’s defeat in that war. He also was prepared to use such weapons in 1991 if the U.S.-led coalition had tried to topple him in the Persian Gulf War.

Before the war, the Bush administration cast Saddam as an immediate threat. Bush said in October 2002 that “Saddam Hussein still has chemical and biological weapons and is increasing his capabilities to make more.” Bush also said then, “The evidence indicates that Iraq is reconstituting its nuclear weapons program.”