Books: Why All Empires Come to Dust THE RISE AND FALL OF THE GREAT POWERS

People have learned to live with the knowledge that they will die. But the evidence that entire nations, apparently invincible behemoths, may be similarly fated has proved the source of enormous curiosity and awe. The Old Testament exclamation "How are the mighty fallen!" was only one of the earliest recorded responses to the spinning wheel of fortune. Ever since, the rubble of old realms has teased and provoked imaginations. In the 18th century, a visit to Rome inspired Gibbon to write an enduring history of imperial decline. Romantic poets found the gloom and doom of antiquity irresistible. Envisioning an ancient toppled monument in a barren desert, Shelley conceived an epitaph that was both ironic and admonitory: "My name is Ozymandias, king of kings:/ Look on my works, ye Mighty, and despair!" In a softer temper, Poe allowed the face of a beautiful woman to transport him back in time "To the glory that was Greece,/ And the grandeur that was Rome."

The spectacle of eclipsed civilizations leads not just to poetry and nostalgia but also to a practical consideration: Is it possible to beat the odds that the past has so clearly posted? One answer is suggested in a new volume that U.S. policymakers and pundits are lugging around in their briefcases, an immense academic history bristling with tables, maps and charts, plus 83 pages of closely printed footnotes and a bibliography that cites nearly 1,400 sources. The book is The Rise and Fall of the Great Powers, by Yale Professor of History Paul Kennedy. Its message, particularly for the U.S. at the present moment, is not encouraging.

Kennedy's study is actually two books in one. The subtitle -- "Economic Change and Military Conflict from 1500 to 2000" -- accurately describes the , bulk of the contents: a sweeping survey of the shifting balance of power over five centuries. The book could easily serve as an introductory history text for very bright undergraduates. But Kennedy is not content to end his story in the present. His final chapter, "To the 21st Century," ventures to predict which nations will prosper and decline in the near future. Astrologers do this sort of thing all the time; when a respected historian tries his hand, people pay attention.

Kennedy's view of the past, and of the years to come, is governed by a central and, on the surface, astonishingly simple thesis: "The historical record suggests that there is a very clear connection in the long run between an individual Great Power's economic rise and fall and its growth and decline as an important military power (or world empire)." If all he were saying is that richer nations tend to win wars, then there would be very little reason for anyone to read further. But Kennedy's argument is more supple than it at first appears. A nation's strength, both in its commerce and on the battlefield, must be measured against that of its rivals and enemies: "So far as the international system is concerned, wealth and power, or economic strength and military strength, are always relative . . . and since all societies are subject to the inexorable tendency to change, then the international balances can never be still."