Very few academic disciplines study simultaneously the Peloponnesian War and today's issue of the New York Times. Current diplomatic practices, such as diplomatic immunity, were created because of circumstances realized millennia ago. 300 B.C. And yet the world is profoundly different now than it was 500 years ago. Henry the Navigator could not even dream of supersonic transport. The condotierri of the Italian Wars would have had a far different impact on human history if they had had access to plastic explosives or nuclear devices.
Constant change is an enduring fixture of international relations.
For the last five hundred years, the world has been increasingly organized along the principles, ideals, and institutions of the European Enlightenment. Let me elaborate on the significance of these three propositions because, as children of the Enlightenment, we tend to take them for granted. The first proposition depreciates alternative political agents such as the tribe, or the clan, or race, or ethnicity, or gender, or the royal house. Political systems have been built upon some of these agents, and there is no necessary reason why these systems could not be made to work. But the Enlightenment's first job was to liberate the individual from the constraints of the monarchy and the church.