The problem with this is that maybe those networks/utilities SHOULDN'T BE ON THE PUBLIC INTERNET. If the military or other government agencies can't defend themselves appropriately, then maybe they should invest in rolling out a completely separate network just for US government purposes. Hell, they did it once (i.e APRANet).
The fallout would be huge!
Agreed, not to mention that the real bread and butter of our nations military and intelligence networks are completely separate from what we know as the internet. There is a huge difference between taking, say, whitehouse.gov or army.mil down verse our real command and control networks--which are probably next to impossible to take down considering there are layers upon layers of backup communication systems.
The idea of a "cyber-attack" being used as a first salvo in an act of war against the United States by any nation-state is pretty ludicrous, as it would minimally (if at all) affect our ability to destroy whoever was dumb enough to try it.