They know the United Nations passed more than a dozen resolutions citing the development and possession of weapons of mass destruction.
This, too, is misleading. These resolutions called on Saddam to declare the state of his WMD arsenal and, if he claimed there was no such thing, to produce records documenting its destruction. The resolutions never claimed—or had the intention of claiming—that he had such weapons.
Saddam did demonstrably have chemical-weapons facilities when the U.N. Security Council started drafting these resolutions. But, as noted by former weapons inspector David Kay (but unnoted in President Bush's speech), President Bill Clinton's 1998 airstrikes destroyed the last of these facilities.
[M]any of these critics supported my opponent during the last election, who explained his position to support the resolution in the Congress this way: "When I vote to give the President of the United States the authority to use force, if necessary, to disarm Saddam Hussein, it is because I believe that a deadly arsenal of mass destruction in his hands is a threat, and a grave threat, to our security."
Bush's opponent, Sen. John Kerry, did utter these words, possibly to his later regret. Still the key phrase is "to use force if necessary." Kerry has since said—as have many other Democrats who voted as he did—that they assumed the president wouldn't use force unless it really was necessary to do so, or unless the intelligence he cited was unambiguous and the threat he envisioned was fairly imminent. This, Bush never did.
That's why more than a hundred Democrats in the House and Senate—who had access to the same intelligence—voted to support removing Saddam Hussein from power.
This is the crucial point: these Democrats did not have "access to the same intelligence." The White House did send Congress a classified National Intelligence Estimate, at nearly 100 pages long, as well as a much shorter executive summary. It could have been (and no doubt was) predicted that very few lawmakers would take the time to read the whole document. The executive summary painted the findings in overly stark terms. And even the NIE did not cite the many dissenting views within the intelligence community. The most thorough legislators, for instance, were not aware until much later of the Energy Department's doubts that Iraq's aluminum tubes were designed for atomic centrifuges—or of the dissent about "mobile biological weapons labs" from the State Department's Bureau of Intelligence and Research.
Intelligence estimates are unwieldy documents, often studded with dissenting footnotes. Legislators and analysts with limited security clearances have often thought they had "access to intelligence," but unless they could see the footnotes, they didn't.
For instance, in the late 1950s, many senators thought President Dwight Eisenhower was either a knave or a fool for denying the existence of a "missile gap." U.S. Air Force Intelligence estimates—leaked to the press and supplied to the Air Force's allies on Capitol Hill—indicated that the Soviet Union would have at least 500 intercontinental ballistic missiles by 1962, far more than the U.S. arsenal. What the "missile gap" hawks didn't know—and Eisenhower did—was that the Central Intelligence Agency had recently acquired new evidence indicating that the Soviets couldn't possibly have more than 50 ICBMs by then—fewer than we would. (As it turned out, photoreconnaissance satellites, which were secretly launched in 1960, revealed that even that number was too high; the Soviets had only a couple of dozen ICBMs.)
So, yes, nearly everyone thought Saddam was building WMDs, just as everyone back in the late '50s thought Nikita Khrushchev was building hundreds of ICBMs. In Saddam's case, many of us outsiders (I include myself among them) figured he'd had biological and chemical weapons before; producing such weapons isn't rocket science; U.N. inspectors had been booted out of Iraq a few years earlier; why wouldn't he have them now?
What we didn't know—and what the Democrats in Congress didn't know either—was that many insiders did have reasons to conclude otherwise. There is also now much reason to believe that top officials—especially Vice President Dick Cheney and the undersecretaries surrounding Donald Rumsfeld in the Pentagon—worked hard to keep those conclusions trapped inside.