In the months leading up to the Iraq war, Saddam Hussein did try to cooperate with United Nations inspectors, a decision that, paradoxically, helped convince the West that he was hiding weapons of mass destruction.
By late 2002, Saddam finally tilted toward trying to persuade the international community that Iraq was cooperating with the inspectors of Unscom (the United Nations Special Commission) and that it no longer had W.M.D. programs. Saddam was insistent that Iraq would give full access to United Nations inspectors "in order not to give President Bush any excuses to start a war."
Ironically, it now appears that some of the actions resulting from Saddam's new policy of cooperation actually helped solidify the coalition's case for war. Over the years, Western intelligence services had obtained many internal Iraqi communications, among them a 1996 memorandum from the director of the Iraqi Intelligence Service directing all subordinates to "insure that there is no equipment, materials, research, studies or books related to manufacturing of the prohibited weapons (chemical, biological, nuclear and missiles) in your site." And when United Nations inspectors went to these research and storage locations, they inevitably discovered lingering evidence of W.M.D.-related programs.
In 2002, therefore, when the United States intercepted a message between two Iraqi Republican Guard corps commanders discussing the removal of the words "nerve agents" from "the wireless instructions," or learned of instructions to "search the area surrounding the headquarters camp and
for any chemical agents, make sure the area is free of chemical containers, and write a report on it," United States analysts viewed this information through the prism of a decade of prior deceit. They had no way of knowing that this time the information reflected the regime's attempt to ensure it was in compliance with United Nations resolutions. What was meant to prevent suspicion thus ended up heightening it.
http://www.nytimes.com/2006/04/30/weekinreview/30reading.html