One hears that many people are reading the memoirs of Robert Gates. So they should. The book is a fascinating study in the role of a senior civil servant in a democratic state. Gates comes across as a consummate servant of the state and a very civil one: incisive, yet with a sense of modesty and proportion. More than any of the details in the book, it was the tone of Gates’s reflections that impressed me most. I found myself thinking of his book as a twenty-first-century counterpoint to Baldassare Castiglione’s celebrated treatise of 1528, The Book of the Courtier.…