Gen. David H. Petraeus closed his phenomenal 37-year Army career this week with a joint review at Fort Myer in Arlington. Service members from every branch were present, and flags of all 50 states fluttered in the breeze. A substantial crowd had come to hear the general’s farewell address. Many were classmates from the West Point Class of 1974, smartly attired but enthusiastic and occasionally whooping like they were cadets. Others were people with whom he had served over his storied career, whom he recognized from the dais during his speech. The morning was sunny and clear, and the general was his usual affable, ebullient self.