Different players in the 2002 debate have different memories. John R. Bolton, the former American ambassador to the United Nations, who headed the State Department’s proliferation office at the time of the 2002 declaration, said in an interview on Wednesday evening that “there was no dissent at the time, because in the face of the evidence the disputes evaporated.” Mr. Bolton, one of the most hawkish voices in the administration and a vocal critic of its recent deal with North Korea, recalled that even the State Department’s own intelligence arm, which was the most skeptical of the Iraq evidence, “agreed with the consensus opinion.”

But David A. Kay, a nuclear expert and former official who in 2003 and 2004 led the American hunt for unconventional arms in Iraq, said he had found the administration’s claims about the North Korean uranium program unpersuasive. “They were driving it way further than the evidence indicated it should go,” he said in an interview. The leap of logic, Dr. Kay added, turned evidence of equipment purchases into “a significant production capability.”

But the doubts were on full display on Wednesday, when Christopher R. Hill, the chief American negotiator with North Korea, testified on Capitol Hill. “If we determine that there is a program, it’s got to go,” Mr. Hill said, words that were far more tentative than American policy makers have used about the program in the past. Expressing his resolve to get to the bottom of the mystery, he added: “We cannot have a situation where we — you know, they pretend to disarm and we pretend to believe them. We need to run this into the ground.” He said that while there was no doubt that North Korea had bought centrifuges from Abdul Qadeer Khan, the rogue Pakistani engineer, there was doubt about “how far they’ve gotten.”

John E. McLaughlin, a former director of central intelligence and the deputy C.I.A. director in 2002, defended the initial North Korean findings as accurate. “At the time we reported this, we had confidence that they were acquiring materials that could give them the capability to do this down the road,” he said in an interview. But no one, he added, “said they had anything up and running. We also made clear that we did not have a confident understanding of how far along they were.”

That confidence has dropped further because inspectors have been banned from North Korea for four years, nearly as long as they were out of Iraq before their readmittance just before the 2003 invasion. In Iraq’s case, intelligence analysts extrapolated from the last information they had to assess what kind of weapons Iraq might be producing.

Outside experts, including David Albright, president of the Institute for Science and International Security, a private group in Washington that tracks nuclear arms, have suggested in recent days that something similar happened in North Korea’s case. “The evidence doesn’t support the extrapolation” to the judgment that North Korea was making crucial strides in its uranium program, Mr. Albright said in an interview. “The extrapolation went too far.”

He said administration analysts were right in thinking that Dr. Khan had sold North Korea about 20 centrifuges. Gen. Pervez Musharraf, the Pakistani president, confirmed that in a memoir published last year. But, Mr. Albright said, intelligence agencies overstated whether North Korea had used those few machines as models to construct row upon row of carbon copies.