Levine created a powerful image of President Lyndon B. Johnson in 1966 by alluding to an almost trivial incident: Johnson exposing the scar on his belly from a recent gall bladder operation. But Mr. Levine turned the scar into a defining physical characteristic of the man. He also turned it into his defining political characteristic because the scar was an outline of a map of Vietnam. The caricature was accurate to the point of prophecy: it showed the wound that was to bring down the president.