The recent foiled terror attacks in the United Kingdom should tell us something about fighting the war on terror.
They were attempted by folks who likely found each other once they were in Britain, not by people from other countries who immigrated as a group with the sole purpose of wreaking havoc. The alleged schemers were educated young people with prestigious careers, not street fighters fresh from a militia. And they were prevented through a combination of luck and domestic police work and investigation (read: through intelligence gathering), not by forces stationed overseas.
This should tell us that the war on terror is a domestic intelligence issue, and any focus on the war in Iraq as "central to preventing terrorism" is a focus sadly misplaced.
That is the real tragedy of the war in Iraq from a strictly selfish point of view. The U.S. and its allies are wasting billions of dollars fighting an imbedded insurgency rooted to Iraq instead of using those resources to prevent terrorism at home. Imagine how safe we could be, how much better our intelligence could be, how many more police and investigators we could put on the tail of domestic sleeper cells if we weren't in the Iraq war.
Unfortunately, this shift in focus won't happen. Partially because those conducting this war on terror are either too stubborn to admit error or simply too blind to notice.