Almost fifty years ago, introducing my biography of Lord Acton, I wrote: “He is of this age, more than of his. He is, indeed, one of our great contemporaries.” A decade and a half later, in an essay on Acton, I described him as being “totally out of sorts with his times”—but I no longer ventured to claim him for our times. Today, almost a century after his death, he seems to me to be even more out of sorts with our age than with his. His governing passions were liberty and morality, religion and history. If he found them all defective in his age, he would have been far more dismayed by what we have made of them.

Yet it is one of the many paradoxes of this extraordinary man that today he is a hero to so many people of such different persuasions and dispositions—liberals and conservatives, libertarians and traditionalists, Catholics, non-Catholics, and non-believers. An eminent Chicago-school eco ...