When you defeat the enemy, you don't send him home. You need him there so you can go home.
The invasion of Iraq was an arrogant abuse of power, a reckless, short-sighted, stupid thing to do. It was even more stupid for former U.S. Ambassador Paul Bremer (who had no military experience) to unilaterally disband the Iraqi Army (euphemistically called "de-Baathification"), which resulted in the U.S.-creation of... a Sunni insurgency and al-Qaida in Iraq.
But more than anything else, President Bush and Ambassador Bremer made a very deadly mistake, a blunder, which has cost the lives of more than 4,400 great Americans and wounded tens of thousands of brave U.S. soldiers. Bush and Bremer's short-sightedness and contempt for military history was evident in their decision, which may become known by military historians as the greatest U.S. military blunder of the 21st Century.