The corruption of the best yields the worst. The most obvious example is Satan, once Lucifer, once first among the angels. A mighty person or institution, if turned to evil, does vastly more harm. A rampant, stampeding elephant outweighs an angry ferret. But what if all the rage and destruction of a maddened pachyderm could be squeezed down into that ferret? Could creep among us unseen, unnoticed? Perhaps even gull us into adopting it as a pet? Then as we grew fond of it, it slowly grew in size. It imperceptibly gained power. Until at last the monster we’d...