There’s an idea in (popular) political science about Pax Romana, the idea that for several hundred years, Ancient Rome’s preponderance of power created an atmosphere of relative peace both inside and outside its borders. This was supported by a massive, well-organized military who’s the job it was to enforce Roman law inside its borders, and suppress any enemies internal or external.
This idea has been applied to other cases, in particular Pax Brittanica and Pax Americana. In all three of these cases, the hegemon has had a dominating military in a specific battlespace compared to any rival. Rome had superior land armies, Britain had superior navies, and the US has a superior air (and space) force. States were thus geared for supporting these forces and reaping the economic benefits they gave. Rome’s armies sustained Rome’s economies through slaves, Britain through mercantile trade, and the US through rapid global soft and hard power projection.
The question therefore is what does the future hold for hegemonic peace? We’re probably in the middle of a Pax Americana so during the next few decades we’ll have 1) continued Pax Americana, 2) a shift of power to a different hegemon (as happened to Pax Britanica at the end of the 19th century), or 3) the world order devolves into having several localized powers that do not necessarily cooperate for mutual peace and gain (as happened after Pax Romana in the Middle Ages). Since military and economic power are tightly linked and interdependent, I believe the new economic shift to the Internet will require a new hegemon to develop and maintain technical and information superiority to challenge the current world order. Many countries, particularly Russia and China, have developed these cyberwarfare capabilities and successfully tested them against adversaries. The US also has significant capabilities but cyberwarfare is so far in such a nascent state that it’s hard to establish dominance. Hopefully, it won’t require a real test like a repeat of the Napoleonic wars or WWI/WWII.