In 1972, on “The Tonight Show,” Johnny Carson asked Truman Capote about capital punishment. Capote had written, in unsettling detail, about the hanging of two killers, Dale Hickock and Perry Smith. Carson said, of the death penalty, “As long as the people don’t have to see it, they seem to be all for it”; if executions occurred “in the public square,” Americans might stop doing them. Capote wasn’t so sure. His hands laced together professorially, he murmured, in his baby-talk drawl, “Human nature is so peculiar that, really, millions of people would watch it and get some sort of vicarious sensation.”
Capote’s book “In Cold Blood,” which began, in 1965, as a four-part series for this magazine, was preoccupied both by the peculiarity of human nature and by the vicarious…