A couple things.

First off while I'm a little fuzzy on the exact laws you can be punished for doing nothing as an innocent bystander. Specifically in regards to not telling what you know and in regards to not getting the victim aid if they are dying.

As for the subject at hand I think it's important to differentiate between groups of civilians. For example we have millions of Muslims in the States who aren't engaging in any terrorist activities and our supporting our government through taxes and the like.

In Iraq much of the citizenry are getting out and voting and hundreds of thousands have signed up for the police and military in the process of taking over the policing of Iraq from the Allies. Plus however many militias are letting us buy them off.

However in any situation collateral damage happens and the more it is a proper state vs state war the wider the range of what consititutes a militarily target becomes.