If your definition of global leadership consists of 2 world wars, several pan-Asian conflicts, war and conflict in areas like the entire Middle East, much of Africa, and large chunks of Central and South America for practically the entire 20th century, then it is clear that our definition of leadership differs greatly.

> consists of 2 world wars

Are you trying to go down the NRx rabbit hole of "World War II could have been avoided"? It's basically a Godwin's Law at this point. Most of the other conflicts you mention are actually American and Russian conflicts, so you're also falling into the trap of "America is the world".