First Lt. Josh Waddell ordered his men to take out an insurgent last fall in Afghanistan, and that decision has come back to bite him pretty badly. Now, the 25-year-old finds himself at the center of a contentious debate over the rules of engagement and the potentially disastrous career implications for those deemed to have violated them. When the incident occurred, Waddell was the executive officer for his company with 3rd Battalion, 7th Marines, which oversaw security in the Sangin district of Helmand province. He was subsequently fired from that job, given a lousy fitness report and told he would…