Imagine There's No America

Waning empires. Religious revivals. Incipient anarchy. A coming retreat into fortified cities. These are the Dark Age experiences that a world without a hyperpower might find itself reliving. The trouble is, of course, that this Dark Age would be an altogether more dangerous one than the one of the ninth century. For the world is roughly 25 times more populous, so that friction between the world's "tribes" is bound to be greater. Technology has transformed production; now societies depend not merely on freshwater and the harvest but also on supplies of mineral oil that are known to be finite. Technology has changed destruction, too: Now it is possible not just to sack a city, but to obliterate it.

Niall Ferguson imagines a world without American hegemony, in "The End of Power" in Monday's "Wall Street Journal." His conclusion? As if you couldn't guess from the reference to "dark ages." It's ugly.

The prospect of an apolar world should frighten us a great deal more than it frightened the heirs of Charlemagne. If the U.S. is to retreat from the role of global hegemon--its fragile self-belief dented by minor reversals--its critics must not pretend that they are ushering in a new era of multipolar harmony. The alternative to unpolarity may not be multipolarity at all. It may be a global vacuum of power. Be careful what you wish for.