This is worth a watch
http://www.ted.com/talks/daniel_suarez_the_kill_decision_sho...
So from a friend that was a major in the USAF flying fixed and rotor wing aircraft: the current UCMJ / ROEs requires an officer present for each and every kill decision. Period. If that doesn't happen, it's get-a-lawyer-and-court-martial time. Probably main US military isn't the biggest threat if the video's fears in the near term, there are too many people watching: it's any force of any country that doesn't respect rules of war.
edit: For clarity.
You can make the argument that there are some very inhumane/barbaric ways to kill people, and as a "civilized" world, we shouldn't engage in them. But, that line of reasoning always takes you back to, "wait, how about we just not kill people at all?"