For decades, the former MI6 intelligence officer David Cornwell—known to the world by his pseudonym, John le Carré—has written espionage novels starring protagonists who regret, but can never escape, the moral compromises of their often duplicitous profession. His spies have combated the Soviets, criminal networks, and terrorists. Even if they used dubious means, le Carré always seemed to assume that their ends were admirable. He no longer does. At 88, he takes up the timely topic of Brexit