If tactics employed in Northern Ireland can be made to work in Iraq (and maybe they can) even though Iraq has ten times as many people as Northern Ireland does and even though Iraqis don't speak English and even though the sectarian violence in Iraq is undergirded by concrete fighting over valuable resources, then does this really seem like a wise strategic undertaking?
The reason you don't see this question being addressed in the mainstream is because of the convention of pretending that the United States military in Iraq is some sort of benign actor beset by violence it cannot explain or understand.
Everyone seems to have agreed that under no circumstances is the US military to be portrayed as what it, in fact, is: one of many belligerent groups in a multisided resource war.
Obviously the US is "the good guys" from our perspective because they are fighting on behalf of US interests, but in no sense are they a legitimate or constructive ordering force in Iraq. They are soldiers in a war zone, fighting against enemies. That's all they'll be until we pull them out. Pretending that they are some sort of Extreme Makeover - Dictatorship Edition contracting crew is killing people. We need to stop it.