The 1991 Persian Gulf War and subsequent U.N. inspections destroyed Iraq's illicit weapons capability and, for the most part, Saddam Hussein did not try to rebuild it, according to an extensive report by the chief U.S. weapons inspector in Iraq that contradicts nearly every prewar assertion made by top administration officials about Iraq.

Charles A. Duelfer, whom the Bush administration chose to complete the U.S. investigation of Iraq's weapons programs, said Hussein's ability to produce nuclear weapons had "decayed" continuously since 1991. Inspectors, he said, found no evidence of "concerted efforts to restart the program."

The findings were similar on biological and chemical weapons. While Hussein had long dreamed of developing an arsenal of biological agents, his stockpiles had been destroyed and research stopped years before the United States led the invasion of Iraq in March 2003. On chemical weapons, Duelfer said Hussein hoped someday to resume an effort after U.N. sanctions ended, but had no stocks and had not researched making the weapons for a dozen years.

Duelfer's report represents the government's most definitive accounting of Hussein's weapons programs, the assumed strength of which the Bush administration presented as a central reason for the war.

President Bush, Vice President Cheney and other top administration officials asserted before the U.S. invasion that Iraq was reconstituting its nuclear weapons program, had chemical and biological weapons, and maintained links to al Qaeda affiliates to whom it might give such weapons to use against the United States.

But after extensive interviews with Hussein and his key lieutenants, Duelfer concluded that Hussein 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, with which Iraq had fought an eight-year war.

-- Dana Priest and Walter Pincus

Charles A. Duelfer speaks before the Senate Armed Services Committee on Wednesday.