Think about what you are saying! Do you think the police are equipped or adequately trained to protect our canals, power plants, reservoirs, nuclear power facilities, the power distribution grid, refineries, and dams? You will need the military to protect these if this war really takes hold as expected. Let's not make foolish decisions.
Armed volunteers (militia) or paid police can defend these targets. Not regular military. I support the men and women in our military, but I do not want them used for domestic law enforcement.
Of course, if our borders were secure, the point would be moot. It's a lot easier to secure 6000 miles of border than literally hundreds of thousands of potential targets. The fact that this isn't being done should raise some red flags.
What do you think about having foreign troops here? Because that's who will be guarding these assets eventually.
The military accomplishes its goals without regard for collateral damage, domestic niceties, or constitutional rights. That's why its personnel are governed under the UCMJ instead of civil and/or constitutional law. (That is also why an international criminal court is such an abomination, by the way.) In pursuit of its objectives, the military is empowered to use whatever force is necessary, including mass destruction of civilian infrastructure and life. Not so the police, who are constrained by the Bill of Rights (at least nominally).
To unleash the power of the military upon a civilian population is to pit a tiger against a tabby cat. Our armed forces were never intended to shoot down their own brothers and sisters.
Speaking of foolish, do you really expect the military to defend the power grid throughout the deserts of the US? You truly believe that this would be an effective use of manpower? You do realize that lines DO break down and get repaired all the time, without any military presence at all, don't you? You also realize that "protecting" reservoirs is basically impossible (consider the already publicized crop-duster plans would not be prevented by ground troops, or even F-16's which would take too long to get there in time... unless you want anti-aircraft guns at every site). "Protecting" dams and canals is a nice idea, but logistically improbable, and a huge waste of resources. Besides, if they take out one of ours, I'm sure they know that the Aswan and the Suez are tasty little targets themselves. (MAD works!) Refineries are more numerous and less dangerous (and therefore less critical) than the nuclear power plants... and there's plenty of security measures at the nukes already, and can easily be handled by local enforcement.
To sum up, there is NO valid reason (and NO effective increase in security at the sites you mentioned) to use the military against American citizens... including the ones who are terrorists. You'll notice that not one single Army, Navy, Air Force, or Marine soldier was used or needed in the apprehension of Richard Jewell (poor guy) or Timothy McVeigh (consipracy theories aside for the moment, no sympathy for him).
This is yet another attempt to morph "law enforcement" into "crime prevention", which is an absolute impossibility. The only result is a loss of Freedom, and yet another huge increase in Federal authority.