If I were writing this paper, I would split it into two sections. The first would be concerned with the creation and early development of a civilization while the second would be concerned with its later development and “stabilization.” Geography would be, in my mind, much more important to the first part of the paper than to the second.
For the first part of the paper, I would lean heavily on Jared Diamond’s Guns, Germs, and Steel. I would use Diamond’s work to show how geographic luck had a tremendous impact on the development of agriculture in any given region of the world. He then goes on to argue that the early development of agriculture led to the development of strong civilizations. Civilizations in places with “good” geography arose and became strong while civilizations in less favorable areas did not. Geography, then, is very important in the foundation of a civilization.
For the second part of the paper, I would argue that geography is less important in determining which civilizations become powerful. Here, I would argue that things like culture and institutions are more important. I would probably introduce the ideas of Max Weber’s The Protestant Ethic and the Spirit of Capitalism as a way to show how things like culture are arguably very important in the later development of a civilization. I might look at how Rome became a dominant power largely because of its institutions and not its geography. I would then look at how Italy, with the same geography as existed in Roman times, never became a dominant power after the fall of Rome.
Thus, I would argue that geography is very important in the early development of a civilization but less so in its later development and stabilization.