I didn't say it was a war on al-qaeda, but I get where you are coming from.
Everyone knows why the US and some western partners invaded Iraq without UN backing, to get their company's into a very lucrative market involving (mainly) oil.
It has back-fired on the US though as the country cannot be secured. It would appear the country is going to pitch itself into civil war with shias and sunnis battling it out for the control of the resources. The kurds live in a practically free, peaceful, semi-autonomous region in the north, which no-one around it likes the idea of.
My personal opinion is that Iran is stirring some stuff up to get a civil war going, as soon as a civil war starts, America has NO CHOICE but to leave, they cannot pick a side to protect, it would alienate a whole raft of Islam that follows that certain sect. This would then open the flood gates to Iranian (and possibly Syrian) infiltration and allow them to get a puppet government in power, who would then control the resources.
Al-qaeda is in Iraq, that is for sure, but I don't think they are the main causes of violence and bloodshed, I think the main contributor is sectarian violence.
On another note in the "War on Terror", the US is getting a bit more active in the area of Governments who Sponser or allow terrorism to take place, i.e. Iran and Hezbollah, Cuba, Venezula, The Taliban in Afghanistan...
I believe the reason the US didn't call for a ceasefire in the recent Lebanese conflict is that they supply arms to Israel for HUGE sums of money, the more they use, the more they buy, right? And the more they destroy, the more someone has to rebuild in Lebanon right? So who might put their hand up and take that opportunity I wonder...
In response to dgridley:
The biggest contributor to terrorism aimed at the USA is infact home-grown. Fact

(take the Oklahoma bombing as the biggest example) They just don't blow themselves up I guess!