In the last days of the battle against the Islamic State group in Syria, when members of the once-fierce caliphate were cornered in a dirt field next to a town called Baghuz, a U.S. military drone circled high overhead, hunting for military targets. But it saw only a large crowd of women and children huddled against a river bank. Without warning, a U.S. F-15E attack jet streaked across the drone’s high-definition field of vision and dropped a 500-pound bomb on the crowd. Then a jet dropped one 2