E Pluribus Nixon Seven years ago, Rick Perlstein, a young and decidedly left-wing historian, accomplished a daring feat: he imagined his way into the hearts and minds of the right-wing idealists who made Goldwaterite conservatism one of the most successful mass movements of the 1960s. The result was Before the Storm: Barry Goldwater and the Unmaking of the American Consensus, a richly detailed narrative of the 1964 election, and a dense and dizzying account of a moment when America was teetering on the verge of a nervous breakdown but didn’t know it yet. Now Perlstein has produced a sequel. If...