Dear citizen of Australia/UK/US.
There is a despotic dictator in Iraq. He threatens this country's considerable commercial interests in the area, including our oil supply. Our country cannot function without a reliable supply of oil. We need to remove him and his ruling family. It will create a temporary power vacumm and perhaps cause some short term civil instability but we will leave that to the Iraquis to deal with, as they have for centuries.
Call me niave, but it could not have been any worse than what happened and is happening could it?