Ever since the end of the Cold War, there has been an assumption that conventional warfare between reasonably developed nation-states had been abolished. During the 1990s, it was expected that the primary purpose of the military would be operations other than war, such as peacekeeping, disaster relief and the change of oppressive regimes. After 9/11, many began speaking of asymmetric warfare and "the long war." Under this model, the United States would be engaged in counterterrorism activities in a broad area of the Islamic world for a very long time. Peer-to-peer conflict seemed obsolete.

There was a profoundly radical idea embedded in this line of thought. Wars between nations or dynastic powers had been a constant condition in Europe, and the rest of the world had been no less violent. Every century had had systemic wars in which the entire international system (increasingly dominated by Europe since the 16th century) had participated. In the 20th century, there were the two World Wars, in the 19th century the Napoleonic Wars, in the 18th century the Seven Years' War, and in the 17th century the Thirty Years' War.