Discussed in this essay:

The World America Made, by Robert Kagan. Alfred A. Knopf. 149 pages. $21.

Call it a hallowed tradition. To invest their views with greater authority, big thinkers—especially those given to pontificating about the course of world history—appropriate bits of wisdom penned by brand-name sages. Nothing adds ballast to an otherwise frothy argument like a pithy quotation from John Quincy Adams or George F. Kennan or Reinhold Niebuhr. In The World America Made, a slim volume of mythopoeia decked out in analytic drag, the historian and pundit Robert Kagan cites all three of those renowned figures.…