It's easy to forget that Senator Ted Kennedy & Company tried their best to defeat the resolution authorizing force to kick Saddam out of Kuwait. It's easy to forget that Iraq had passed frequent International Atomic Energy Agency (IAEA) inspections designed to ensure its compliance with the Nuclear Non-Proliferation Treaty (NPT) or that its Manhattan Project-sized nuclear program went undetected by US intelligence. It's also easy to forget just how skilled Saddam became at deception post-Osirak.
Some history --
Iraq ratified the NPT in 1969. Twelve year later, Israel bombed the Osirak nuclear reactor near Baghdad. According to the June 22, 1981 Newsweek,
[t]he Osirak reactor was theoretically only for research purposes—but Iraq twice refused a French offer to supply it with low-enriched uranium, insisting instead on weapons-grade, 93 per cent enriched fuel. Iraq was also operating an Italian-built “hot cell” lab for extracting plutonium, and had arranged to buy large quantities of uranium from Brazil, Portugal and Niger—all without any investment in a nuclear-energy program.
In his 2002 book, The Threatening Storm, Clinton NSC official Kenneth Pollack wrote that Osirak “was the key to Saddam’s nuclear weapons program and ... was due to go online within a matter of weeks.” The bombing set Iraq’s “nuclear bomb program back by several years,” but it also “taught the Iraqis an important lesson. Thereafter, Saddam ordered a redoubling of the Iraqi program...camouflaged against detection.” (Pollack would subsequently note this regarding Saddam's nuclear program.)
After the Osirak attack, Iraq would pursue a secret nuclear weapons program that had gone undetected by Western intelligence and the IAEA until after the 1991 Gulf War. As former U.N. inspector David Kay wrote in a 1995 Washington Quarterly piece, Iraq would pursue this program while maintaining “its status as a full member” of the NPT because it was “the desire of the military and security services not to attract any undue attention to Iraq’s developing nuclear program that would complicate procurement and development efforts.”
The fact that Hussein was able to conceal his nuclear program was even more remarkable given that: 1) as the Washington Post noted in October 1991, the “scope and sophistication” of its program “resembled the Manhattan Project, the American effort that produced the first atomic bomb”; and 2) Iraq had passed regular inspections by the International Atomic Energy Agency.
On August 11, 1991, the Post reported that:
International inspectors...unearthed one of the most important—and disturbing—finds of the post-Cold War era: a huge assembly line for the covert manufacture of equipment to make an Iraqi bomb.
The location of the sophisticated, secret factory for manufacturing hundreds of uranium gas centrifuges was unknown to any foreign intelligence agency despite intense scrutiny and untouched by five weeks of severe aerial bombardment during the Gulf War that supposedly eviscerated the Iraqi nuclear project. As such, it is a monument to the world’s ignorance about what a determined bomb-builder such as Iraqi leader Saddam Hussein can do.
The factory was a key component in Iraq’s elaborate highly redundant and largely secret network of physics, chemistry and metallurgical laboratories, industrial mines, metalworking factories, electrical power generators, nuclear research reactors and radioactive waste processing sites—all aimed at swiftly putting a nuclear weapon in the hands of one of the world’s most ruthless leaders.
The Post also reported:
Despite repeated warnings and Saddam’s own public statements, Western experts consistently underestimated Iraq’s scientific and technical capabilities. Inspection officials now believe Iraq was only 12 to 18 months from producing its first bomb, not five to 10 years as previously thought.Kay wrote that Iraq hid its program by keeping it “heavily compartmentalized” and employing a variety of deception techniques. For example, Iraq created a network of front companies to import nuclear-related materials “in quantities that were below the size that triggered controls.” Equipment was imported ostensibly for civilian purposes but was diverted to the nuclear program as well. (see here for UNMOVIC May 2003 report on Iraq's attempt to "conceal the extent of its import activities and to preserve its importing networks" for missiles, chems & bios)
The Iraqis, Kay continued, had an “accurate understanding of the limitations of U.S. technical collection systems...” and exploited these vulnerabilities through various methods, including:
construction of buildings within buildings... hiding power and water feeds to mislead as to facility use... diminishing value of a facility by apparent low security and lack of defenses... moving critical pieces of equipment at night....