Countries, not individuals, are the enemies and friends that Charles Kupchan has in mind in How Enemies Become Friends, and beginning with the book's title, he sets himself against the most influential school of thought in international relations.
Nations as friends? The redoubtable British foreign secretary Viscount Palmerston announced to the House of Commons in 1848: "As to the romantic notion that nations or Governments are much or permanently influenced by friendships, . . . I say that those who maintain those romantic notions, and apply the intercourse of individuals to the intercourse of nations, are indulging in a vain dream." Palmerston's statement belongs squarely in the tradition of political realism, exemplified by thinkers from St. Augustine to Reinhold Niebuhr.