The video comes with several caveats. First, the warning soldiers always give about viewing things like this: Videos simply don't capture the complexity, pressures and confusion of modern warfare, they say. Things may look one way, now, on video, but in the heat of battle, it's likely that they seemed a lot different to those involved.
Second, the video may not show Americans doing anything wrong -- or at least not illegal under the Law of Armed Conflict. The shorthand version of that law is that you can kill the enemy, period. The gray area in asymmetrical warfare, however, is determining just who the enemy is. Given those ambiguities, in a military courtroom a jury would have to determine if the shooter "honestly and reasonably" believed he was shooting the enemy, according to Gary Solis, an expert on military law at Georgetown University. "That will always be a defense," he told Salon.