[vernarial]

Well I believe they use it to keep the the citizens at a low level of fear. This pertains to the "War on Terror" in general. Keeping us slightly worried about being attacked helps them pass laws to help control the population. Such as the so called Patriot Act. It also helps them maintain and even increase military spending which helps all of their elite buddies who all but run the industry. Like Halliburton who is building several massive military bases in the middle east.
Mostly you have the elite individuals who control the money and power. They use the "War on Terror" and such to further consolidate the power and wealth into the hands of fewer and fewer individuals. It's not just the USA, or the politicians, who benefit from a war on terrorism. Terrorism has been used in the past as an excuse to weaken civil liberties and consolidate power and wealth.
The war in Iraq is just a symptom of an ongoing effort by the powers that be to control populations and consolidate wealth and power.