Failings exposed last spring at a U.S. nuclear missile base, reflecting what one officer called "rot" in the ranks, were worse than originally reported. Airmen responsible for missile operations at Minot Air Force Base, N.D., passed an inspection in March 2013 with a "marginal" rating, the equivalent of a "D" in school. But it now turns out that even that was only because of good marks received by support staff like cooks and facilities managers. Launch officers entrusted with the keys to the missiles did poorly and, on their own, would have flunked, the records show.