In recent years, the most esteemed officer in America—the very model of the modern general—was David Petraeus, whose public image combined the theorizing of the new school with a patina of old-fashioned toughness and rectitude. Before a sex scandal forced him to step down as the director of the C.I.A., a few weeks ago, he was widely regarded by politicians and journalists as a brilliant thinker and leader, the man who saved America in Iraq and might work a similar miracle in Afghanistan. Roger Ailes suggested, perhaps less than half in jest, that Petraeus run for President. Now many of the same people are calling into question not just his ethics but his basic ideas and achievements. History often forgives military leaders for small scandals, if they are successful enough. Eisenhower’s long-alleged affair with Kay Summersby has not much tarnished his reputation as an officer; even Hood, whose late campaigns were disastrous, is remembered as a paragon of bravery, if not of good planning. Will Petraeus be thought of, in time, as a hero guilty of no more than a distracting foible? Or as the general most responsible for two disastrous wars?