The more he read, the more uneasy he became. In early February 2003 Colin Powell was putting the finishing touches on his speech to the United Nations spelling out the case for war in Iraq. Across the Potomac River, a Pentagon intelligence analyst going over the facts in the speech was alarmed at how shaky that case was. Powell's presentation relied heavily on the claims of one especially dubious Iraqi defector, dubbed "Curve Ball" inside the intel community. A self-proclaimed chemical engineer who was the brother of a top aide to Iraqi National Congress chief Ahmad Chalabi, Curve Ball had told the German intelligence service that Iraq had a fleet of seven mobile labs used to manufacture deadly biological weapons. But nobody inside the U.S. government had ever actually spoken to the informant--except the Pentagon analyst, who concluded the man was an alcoholic and utterly useless as a source. He recalled that Curve Ball had shown up for their only meeting nursing a "terrible hangover."

After reading Powell's speech, the analyst decided he had to speak up, according to a devastating report from the Senate intelligence committee, released last week, on intelligence failures leading up to the Iraq war. He wrote an urgent e-mail to a top CIA official warning that there were even questions about whether Curve Ball "was who he said he was." Could Powell really rely on such an informant as the "backbone" for the U.S. government's claims that Iraq had a continuing biological-weapons program? The CIA official quickly responded: "Let's keep in mind the fact that this war's going to happen regardless of what Curve Ball said or didn't say," he wrote. "The Powers That Be probably aren't terribly interested in whether Curve Ball knows what he's talking about."

The saga of Curve Ball is just one of many wince-inducing moments to be found in the 500-page Senate report, which lays out how the U.S. intelligence community utterly failed to accurately assess the state of Saddam Hussein's programs for weapons of mass destruction--and how White House and Pentagon officials, intent on taking the country to war, unquestioningly embraced the flawed conclusions. In startling detail, the bipartisan report concludes that the CIA and other agencies consistently "overstated" the evidence that Iraq possessed chemical and biological weapons, and was actively reconstituting its nuclear-weapons program. Hampered by a "group think" dynamic that caused them to view all Iraqi actions in the harshest possible light, the committee found, U.S. intelligence officials repeatedly embellished fragmentary and ambiguous pieces of evidence, making the danger posed by Iraq appear far more urgent than it actually was.

When U.N. inspectors returned to Iraq in the fall of 2002 and reported that they couldn't find any Iraqi weapons of mass destruction, for instance, the CIA dismissed the inspectors as gullible neophytes who were being tricked by deceitful Iraqi handlers. Similarly, when several Iraqi officials and scientists stepped forward to claim that Saddam had actually destroyed his WMD stockpiles and discontinued his programs (a claim that appears increasingly likely to have been the truth), they were branded as liars--while dubious sources like Curve Ball, whose stories were in step with the administration, were embraced.

Taken together, the facts in the report show that virtually every major claim President George W. Bush used to justify the invasion of Iraq--from Saddam's growing nuclear program to his close ties with Al Qaeda--was either wrong or exaggerated. The CIA was so convinced that Saddam was seeking to rebuild nuclear weapons that it "lost objectivity," the report concludes. The problem was compounded by the fact that the CIA did not have a single human spy inside Iraq after 1998 to report on what was really going on in Saddam's weapons program. Why not? The agency apparently didn't want to take the risk. "It's very hard to sustain... it takes a rare officer who can go in... and survive scrutiny for a long time," the agency told the panel, which cited the responses as evidence of the "risk averse" corporate culture of the CIA. "Leading up to September 11, our government didn't connect the dots," said Sen. John D. Rockefeller IV, the ranking Democrat on the committee. "In Iraq we are even more culpable, because the dots themselves never existed."

The report did offer the administration one consolation: the investigators said they found no overt evidence that intelligence-community officials were directly pressured to distort their findings. Seizing on that conclusion, White House aides tried to make the best of the damaging report, saying it proved that the president had been given bad information. "Listen, we thought there was going to be stockpiles of weapons. I thought so; the Congress thought so; the U.N. thought so," Bush told an audience last week. The president showed no signs of having had any second thoughts about the wisdom of the invasion.

Other Republicans weren't so sure. Asked whether Congress would have authorized an invasion had it known two years ago what it knows now, Senate intelligence-committee chairman Pat Roberts, a loyal White House ally, said bluntly, "I don't know." He himself might have voted for a war more "like Bosnia and Kosovo"--a bombing campaign where no U.S. ground troops were put in harm's way.

Though the Republican-led committee officially concluded that nobody ordered intelligence analysts to tailor their findings, the question of whether political pressure influenced intelligence decisions leading up to the war has yet to be laid to rest. There were repeated clashes between committee Democrats and Republicans on the issue. Some Democrats on the committee complained that the report gives an incomplete and inaccurate picture of what really happened, since Republicans insisted on taking up the damaging topic of pressure in a second report--to be issued after the presidential election.

The report itself points to examples of possible political meddling, especially on the issue of whether Iraq had ties to Al Qaeda. Some U.S. intelligence analysts complained to the CIA ombudsman that "the constant questions and requests to reexamine the issue of Iraq's links to terrorism [were] unreasonable and took away from their valuable analytic time." When the CIA reached a measured and ambiguous view of the connection--"Iraq and Al-Qaeda: Interpreting a Murky Relationship" was the title of one June 2002 report--a team of Pentagon hard-liners under the direction of Under Secretary of Defense for Policy Douglas Feith strongly challenged the agency's conclusions. An August 2002 briefing that the Pentagon team gave to the then CIA Director George Tenet pushed evidence that Iraq might have been involved in the 9/11 attack. Their prime piece of evidence: alleged meetings in Prague between lead hijacker Muhammad Atta and an Iraqi intelligence agent. In fact, the committee found that the meetings likely never occurred. The Pentagon team brandished a photo of a supposed October 1999 meeting between Atta and the Iraqi agent that turned out to be bogus. The Qaeda terrorist was actually in Egypt visiting his family when the rendezvous supposedly took place. Tenet "didn't think much of" the briefing, he told committee investigators, so the Pentagon team took its case to Lewis (Scooter) Libby, Vice President Dick Cheney's chief of staff, and Stephen Hadley, the deputy national-security adviser. There they found a much more receptive audience. Libby asked for follow-up, including "a chronology of Atta's travels."

The committee report may be just the beginning of the president's political troubles this month. Next up is the long-awaited 9-11 Commission report, which is expected to be highly critical of administration agencies for failing to "connect the dots" that might have prevented the terror attacks. NEWSWEEK has learned that the commission has decided to release its findings next week, so they don't coincide with the Democratic Party convention in Boston at the end of the month. Commission officials say they don't want their work to get caught up in the politics of the presidential campaign. It was a nice thought, anyway.