Depiction of Threat Outgrew Supporting Evidence

* In the weeks and months following Joe's Vienna briefing, Secretary of State Colin L. Powell and others continued to describe the use of such tubes for rockets as an implausible hypothesis, even after U.S. analysts collected and photographed in Iraq a virtually identical tube marked with the logo of the Medusa's Italian manufacturer and the words, in English, "81mm rocket."

* The escalation of nuclear rhetoric a year ago, including the introduction of the term "mushroom cloud" into the debate, coincided with the formation of a White House Iraq Group, or WHIG, a task force assigned to "educate the public" about the threat from Hussein, as a participant put it.

Two senior policymakers, who supported the war, said in unauthorized interviews that the administration greatly overstated Iraq's near-term nuclear potential.

"I never cared about the 'imminent threat,' " said one of the policymakers, with directly relevant responsibilities. "The threat was there in [Hussein's] presence in office. To me, just knowing what it takes to have a nuclear weapons program, he needed a lot of equipment. You can stare at the yellowcake [uranium ore] all you want. You need to convert it to gas and enrich it. That does not constitute an imminent threat, and the people who were saying that, I think, did not fully appreciate the difficulties and effort involved in producing the nuclear material and the physics package."

No White House, Pentagon or State Department policymaker agreed to speak on the record for this report about the administration's nuclear case. Answering questions Thursday before the National Association of Black Journalists, national security adviser Condoleezza Rice said she is "certain to this day that this regime was a threat, that it was pursuing a nuclear weapon, that it had biological and chemical weapons, that it had used them." White House officials referred all questions of detail to Tenet.

In an interview and a four-page written statement, Tenet defended the NIE prepared under his supervision in October. In that estimate, U.S. intelligence analysts judged that Hussein was intent on acquiring a nuclear weapon and was trying to rebuild the capability to make one.

"We stand behind the judgments of the NIE" based on the evidence available at the time, Tenet said, and "the soundness and integrity of our process." The estimate was "the product of years of reporting and intelligence collection, analyzed by numerous experts in several different agencies."

Tenet said the time to "decide who was right and who was wrong" about prewar intelligence will not come until the Iraqi Survey Group, the CIA-directed, U.S. military postwar study in Iraq of Hussein's weapons of mass destruction programs is completed. The Bush administration has said this will require months or years.

The possibility of a nuclear-armed Iraq loomed large in the Bush administration's efforts to convince the American public of the need for a preemptive strike. Beginning last August, Cheney portrayed Hussein's nuclear ambitions as a "mortal threat" to the United States. In the fall and winter, Rice, then Bush, marshaled the dreaded image of a "mushroom cloud."

By many accounts, including those of career officials who did not support the war, there were good reasons for concern that the Iraqi president might revive a program to enrich uranium to weapons grade and fabricate a working bomb. He had a well-demonstrated aspiration for nuclear weapons, a proficient scientific and engineering cadre, a history of covert development and a domestic supply of unrefined uranium ore. Iraq was generally believed to have kept the technical documentation for two advanced German centrifuge designs and the assembly diagrams for at least one type of "implosion device," which detonates a nuclear core.

What Hussein did not have was the principal requirement for a nuclear weapon, a sufficient quantity of highly enriched uranium or plutonium. And the U.S. government, authoritative intelligence officials said, had only circumstantial evidence that Iraq was trying to obtain those materials.

But the Bush administration had reasons to imagine the worst. The CIA had faced searing criticism for its failures to foresee India's resumption of nuclear testing in 1998 and to "connect the dots" pointing to al Qaeda's attacks of Sept. 11, 2001. Cheney, the administration's most influential advocate of a worst-case analysis, had been powerfully influenced by his experience as defense secretary just after the Persian Gulf War of 1991.