SIMI VALLEY - Shawn Sage long dreamed of joining the military, and watching "Full Metal Jacket" last year really sold him on becoming a Marine. But last fall, a Los Angeles Superior Court commissioner dashed the foster teen's hopes of early enlistment for Marine sniper duty, plus a potential $10,000 signing bonus. In denying the Royal High School student delayed entry into the Marine Corps, Children's Court Commissioner Marilyn Mackel reportedly told Sage and a recruiter that she didn't approve of the Iraq war, didn't trust recruiters and didn't support the military. "The judge said she didn't support the Iraq...