The whole "Is hacking an act of war?" thing needs to be seriously reconsidered. Of course, if the US decided it was, they would be guilty of so many acts of war. And it's not just the US. Everybody is trying to hack everybody and acting like killing people by bringing down a power grid is somehow different than killing people by dropping a bomb. The outcome is the same: You did something that intentionally killed people.
Of course saying that hacking is an act of war opens up a huge can of worms. Suddenly small time hackers are being charged with or framed for war crimes.
It's a delicate issue, but I think it is worth revisiting.