In August 1998, Ritter resigned his position as UN weapons inspector and sharply criticized the Clinton administration and the UN Security Council for not being vigorous enough about insisting that Iraq's weapons of mass destruction be destroyed. Ritter also accused UN Secretary General Kofi Annan of assisting Iraqi efforts at impeding UNSCOM's work. "Iraq is not disarming", Ritter said on August 27, 1998, and in a second statement, "Iraq retains the capability to launch a chemical strike."<quoted text>
The Second Persian Gulf War, also known as the Iraq War, Mar.–Apr., 2003, was a largely U.S.-British invasion of Iraq. In many ways the final, delayed campaign of the First Persian Gulf War, it arose in part because the Iraqi government failed to cooperate fully with UN weapons inspections in the years following the first conflict.
However, by 1999, he reversed his opinion.
In June, 1999, Ritter responded to an interviewer, saying: "When you ask the question,'Does Iraq possess militarily viable biological or chemical weapons?' the answer is no! It is a resounding NO. Can Iraq produce today chemical weapons on a meaningful scale? No! Can Iraq produce biological weapons on a meaningful scale? No! Ballistic missiles? No! It is 'no' across the board. So from a qualitative standpoint, Iraq has been disarmed. Iraq today possesses no meaningful weapons of mass destruction capability."
In 2002, Scott Ritter stated that, as of 1998, 90–95% of Iraq's nuclear, biological and chemical capabilities, and long-range ballistic missiles capable of delivering such weapons, had been verified as destroyed. Technical 100% verification was not possible, said Ritter, not because Iraq still had any hidden weapons, but because Iraq had preemptively destroyed some stockpiles and claimed they had never existed. Many people were surprised by Ritter's turnaround in his view of Iraq during a period when no inspections were made. During the 2002–2003 build-up to war Ritter criticized the Bush Administration and maintained that it had provided no credible evidence that Iraq had reconstituted a significant WMD capability.
In January 2003, United Nations weapons inspectors reported that they had found no indication that Iraq possessed nuclear weapons or an active program. Some former UNSCOM inspectors disagree about whether the United States could know for certain whether or not Iraq had renewed production of weapons of mass destruction. Robert Gallucci said, "If Iraq had uranium or plutonium, a fair assessment would be they could fabricate a nuclear weapon, and there's no reason for us to assume we'd find out if they had." Similarly, former inspector Jonathan Tucker said, "Nobody really knows what Iraq has. You really can't tell from a satellite image what's going on inside a factory."