As more details emerge in Sunday's slaughter of 16 Afghan civilians, the Wall Street Journal reports on an unfortunate "what if." It turns out that the small base where the accused Army staff sergeant was stationed was aware he left around 3am, thanks to an Afghan soldier who spotted him walking out and alerted post commanders. A search party was even being launched just as news of the murders reached the base. Had that search been successful, the murders could have been averted, posits the Journal. Click for more on the suspected shooter, who had reportedly suffered a traumatic brain injury on a previous tour of duty. (More Afghanistan stories.)