The correct answer to this open question is the following.
The Iraq War is a subject of much debate because of the way the United States government decided to invade the Middle East country.
The Security Council of the United Nations had sent "blue helmets" soldiers to verify the existence of mass destruction weapons in Iraq, and have confirmed nothing. US President George W. Bush did not wait until the Security Council had a final decision and he decided to sent troops to invade Iraq under the argument that Sadam Hussein had many mass destruction weapons. The controversy increased when the US troops and UN "blue helmets" did not find any evidence about those weapons.