According to U.S. officials, they had no legal authority to intervene. One video taken by the exiles even shows soldiers get into a white sport utility vehicle and roll up their windows as the bloodied men plead for help.
I'm skeptical of this. I'd like to know where the video is. I saw other videos when the story first came out (bunch of links here - full disclosure: it's my blog). I also wonder about the quote above - perhaps JMM or someone else here knows the answer. On every deployment that I went on in two countries - peacekeeping, HIC, or COIN - our ROE included the right to intervene in a situation to defend the life of a noncombatant. Indeed, such actions accounted for the majority of our actions in 2003, when we occupied Baghdad. Most of the shots that we fired in the summer of 03 were in defense of civilians being assaulted by criminal gangs (attempted kidnappings, robberies, murders, etc).