When Jiang Zemin saw “Titanic,” he was extremely impressed. Was it the film’s politics? The scuffling between the disadvantaged proletariat below decks and preening nobs above? Sure, James Cameron’s blockbuster displayed a rudimentary class consciousness, of the sort that a Communist leader might be expected to note and grimly endorse. But that wasn’t what earned the particular admiration of the president of the People’s Republic of China. No — Jiang, reports Erich Schwartzel in “Red Carpet,” was blown away by the movie’s “emotional appeal”: Leo and Kate, the gale-like voice of Celine Dion, the artistic engineering of the feelings. “I invite my comrades of the Politburo to see the movie,” he said at the next National People’s Congress. “We should never think that we are the only ones who know how to persuade people.”