While diplomats from 70 nations—including Hillary Clinton—gathered in Kabul to discuss the path toward a self-sufficient Afghan military, a tragic example of the hurdles along the way unfolded at a weapons base in the north of the country. During a routine training course, a renegade Afghan army trainer opened fire on his fellow instructors, killing two U.S. civilians, another Afghan soldier, and ultimately himself. Further details have yet to emerge, but a British NATO spokesman called the event "a great tragedy," and officials have already opened a joint investigation into the matter. Though expanding Afghanistan's military is a top priority for both the government and the NATO coalition occupying the country, today's loss left some wondering if eligibility requirements are too loose. "The security process is in place," a NATO authority said, but added: "It's not infallible."