Sorry Rasoul jaan, I don't believe my use of the word declassified was fully justified or proper. However, I trust the following should be sufficient examples that this would not be a quick wham bam thank you Saddam solution. Obviously as you have stated there is no 100% way of knowing anything, but a good leader would make the best decision based on ALL perspectives offered to him and based just on what I'm presenting below (and I'm sure there are many other examples) it wouldn't have taken a genius to put 2 and 2 together.
* New York times reported on 08/0202 a panel of experts on Iraq "warnning" the Senate Foreign Relations Committee: “Nearly all the experts argued that setting up a stable, pro-Western government in Baghdad would require a huge infusion of aid and a long term commitment of American troops to maintain peace.”
* Wall Street Journal on 08/25/02 prints a column from Brent Scowdraft saying that "the toppling of Saddam’s regime would destabilize the Middle East and thus “turn the whole region into a cauldron and destroy the War on Terror.”
09/04/2002 The Washington Post reports former Navy Secretary saying the administration will put US in Iraq for decades. "The issue before us is not simply whether the United States should end the regime of Saddam Hussein, but whether we as a nation are prepared to physically occupy territory in the Middle East for the next 30 to 50 years. Those who are pushing for a unilateral war in Iraq know full well that there is no exit strategy if we invade and stay.”
The rest, I'll just provide as summaries:
September 15, 2002: White House Economic Adviser Says Iraq Invasion Will Cost Up to $200 Billion
September 30, 2002: Congressional Budget Office Says Occupation of Iraq Could Cost Over $272 Billion
November 2002: Wilson (former US dimplomat): Iraq Occupation Will Be a ‘Very Nasty Affair’
November 1, 2002: Middle East Expert Predicts US Invasion of Iraq Will Lead to More Recruits for Al-Qaeda
January 2003: CIA Analyst Warns in Paper That Establishing Democracy in Iraq Will Not Be Easy; Ethnic and Religious Divisions May Fuel Violence
Late January 2003: US Army War College Report Predicts Civil War in Post-Saddam Iraq
February 16, 2003: Experts Estimate Cost of Iraq War at up to $682 Billion
February 25, 2003: Top Army General Says ‘Several Hundred Thousand Soldiers’ Will Be Needed to Secure Iraq
February 26, 2003: Classified State Department Report Predicts Civil Unrest and Sectarian Violence in Post-Invasion Iraq
December 3, 2003: Study Finds Iraq Invasion Could Cost Almost $2 Trillion