Have you ever wondered about what causes great powers to rise and fall throughout history? This is a favorite topic of historians1 from the ancient Greeks and Romans themselves to the present day. Just as it is unclear exactly how much longer we will live individually, or how prosperous our lives will be, the future lifespan and prosperity of the states to which we belong are mysterious. We therefore have a reasonable desire to understand the underlying forces at work to help us better plan for subsequent developments and mitigate any ill effects.
As I write this, the United States of America is about to celebrate the 250th anniversary of its declaration of independence from the British Empire. Looking back from then to now, it is impressive that some colonies with a fraction of Britain’s power were able to eventually eclipse it so thoroughly. This milestone naturally invites reflection on the past, present, and future trajectory of the country.
For me, the number recalled a brief work I read several years ago called The Fate of Empires by John Glubb. It is only 25 pages and I would recommend it to anyone interested in the titular subject. One of its central theses is that the average lifespan of empires is 250 years, regardless of the time or place. This makes the present anniversary much more ominous than it initially appears.
Here, the term “empire” refers to the period when a political entity exercises its power across vast territories, regardless of its system of government. This invites some degree of relativity, and I think “great power” or “superpower” might be closer to the mark, but generally you know it when you see it. Glubb is most familiar with the histories of Europe, the Middle East, and North Africa, which is reflected in his list of empires alongside their durations reproduced here:
| The nation | Dates of rise and fall | Duration in years |
|---|---|---|
| Assyria | 859–612 B.C. | 247 |
| Persia (Cyrus and his descendants) | 538–330 B.C. | 208 |
| Greece (Alexander and his successors) | 331–100 B.C. | 231 |
| Roman Republic | 260–27 B.C. | 233 |
| Roman Empire | 27 B.C.–A.D. 180 | 207 |
| Arab Empire | A.D. 634–880 | 246 |
| Mameluke Empire | 1250–1517 | 267 |
| Ottoman Empire | 1320–1570 | 250 |
| Spain | 1500–1750 | 250 |
| Romanov Russia | 1682–1916 | 234 |
| Britain | 1700–1950 | 250 |
Many of these seem accurate, so far as I can tell. The division of Rome into republican and imperial periods is somewhat arbitrary, as the government did change but so many of the underlying structures remained constant that it seems more like one constant life cycle than two distinct ones. The continuity of the Byzantine/Eastern Roman government is also ignored, though they could be seen as undergoing their own distinct life cycle as a Greek power that had to be reforged in the 6th and 7th centuries. This would be much like the case of the Umayyad Caliphate in Spain, which split off from the wider Islamic empire after a few centuries and underwent its own cycle of decline. A few other powers like China or Ancient Egypt historically remained powerful for longer than 250 years, but based on my cursory knowledge individual dynasties tended to last around this length, separated by civil wars or other conflicts. Also, many powers are much shorter-lived than 250 years, showing that this is more of a variable “maximum lifespan” which may not be attained if an empire is ended by other causes.
Glubb divides empires into stages much like the life cycle of a human being, including ages of Pioneers, Conquests, Commerce, Affluence, Intellect, and Decadence, in that order. These have some overlap with one another, as they are not mutually exclusive. It is noteworthy that the intellectual phase happens in the midst of affluence and decadence that presages a decline, especially since Glubb himself is an intellectual. This seems fitting not only in light of his other examples but considering that he was writing in the 1970s amid the UK’s decline as a global power.
One of his interesting postulates is that the rise of empires is difficult to predict because they emerge from peoples previously subjugated to or on the margins of great powers, such as the Arabs, Mongols, Mamluk slaves, American colonies, and others. He posits this as a sudden outburst, which is true in some cases but can also take much longer, closer to the century or two it took to build the Roman, Ottoman, English, or American empires. There is also a necessary period of internal consolidation before outward expansion can occur, including the Roman conquest of Italy, Muslim conquest of Arabia, Castilian conquest of Spain, Ottoman conquest of Anatolia, English conquest of the British Isles, or American conquest of the Eastern Seaboard. Based on these criteria it is hard to predict which empires may arise in the near future.
One limitation of this work is that it neglects the role of technology. Historical developments including chariots, bronze, gunpowder, sailing/shipbuilding techniques, vaccines, and so on have all served as opportunities for the development of new empires. Glubb acknowledges that tech allows empires to become more territorially disparate, but maintains that it hasn’t changed their overall trajectories. While technology diffuses over time, he would argue that the willingness and ability of “decadent” people to use those means to pursue their goals diminishes relative to others. This seems broadly correct through the current day, as shown by US military setbacks against foes such as Afghanistan and Iran who have greatly inferior resources at their disposal. No matter what the ends of your empire are, you need both sufficient resources and the ability plus the resolve to use them or you won’t have the means to keep it. Still, given the imminent feasibility of autonomous land, air, and sea drones, there is an interesting possibility that resources could finally make up for any shortcomings of the people employing them. This could herald an entirely unprecedented age, which I will explore in my next post.
It is still hard to know what the fate of the United States will be based on all these trends. According to the 250 year cycle, a transition to a different government could occur as it did in ancient Rome, Egypt, or China. What makes an internal change or collapse more likely than an externally induced one is the lack of plausible conquerors who could overcome the formidable strength and geographical barriers that would oppose them. It’s unclear exactly what such an internal change would look like, but it’s worth thinking about and preparing for.
Footnotes
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especially amateurs, counting myself among these. ↩