There are many factors that can be linked to the downfall of great kingdoms, empires, and dynasties. It is very difficult to know which of them are the most important in some cases because we cannot be completely sure why such things fall. Among the factors that are often said to lead to the downfall of major powers are:
- Environmental overload. In his book Collapse, Jared Diamond makes this point very strongly. He argues that the Maya, for example, fell because they came to have too many people for their environment. Other scholars have pointed to this as a reason for the weakening of Greece and even of the early civilizations in Mesopotamia.
- Overextension. This is most famous as a proposed cause of the fall of the Roman Empire. Great powers often think that they can continue to expand indefinitely. At some point, they often expand farther than they should. They come to have problems defending their territory militarily, for example, and they fall.
- Internal conflicts. Great empires often have to deal with internal conflict. This can come in the form of conflict over who should rule. Alexander the Great’s empire fell apart because various people disagreed about who should rule after his death. The conflict can also come in the form of discontent on the part of citizens. The Soviet Union fell apart largely because its people were not happy with their economic or political situation.
- Rise of newer, larger powers. A classic example of this was the fall of the British Empire. The British fell from their status as a dominant world power when larger powers came to exist. The British were unable to win WWII without American (and Soviet) help and the war left them weaker than the US. The US simply was bigger, richer and stronger and was therefore positioned to supplant Britain as the major power in the world.