Cartoonist Pat Oliphant in 1998, at an exhibition of his work at the Susan Conway Gallery in Washington. (Frank Johnston/The Washington Post) When Pat Oliphant assembled his entry for the 1967 Pulitzer Prize for editorial cartooning, he included a dozen cartoons he had drawn for the Denver Post: 11 he was proud of, and one he didn’t think was any good but was targeted to appeal to the jury’s politics.He won the prize - for the one cartoon he didn’t like, an image of North Vietnamese leader Ho Chi Minh holding a dead body, captioned, “They won’t get us to...