The idea that the environment within which people interact has an impact on their behavior is anything but radical. Indeed, to urban architects, physicians, sociologists, economists, and policy analysts, it will seem commonplace. And because people are both aware of the impact of their environment and able to alter it, it comes as little surprise that we seek to do so: strategic placement of one-way streets eases traffic congestion, snack machines with healthier options improve diets, restructuring government subsidies alters consumer behavior. The combination of these two ideas – that environments have an impact on people's behavior and that people act to alter their environment – is the essence of systemic thinking.

This mode of thinking has made remarkably little headway in the field of international relations. We generally take key elements in the international environment as given: the balance of power, for example, is seen to be either immutable or something that changes of its own accord. Not only do we not understand how people seek, collectively, to influence the international environment within which they interact, but – almost entirely without exception – we do not even try. This is a problem because for many of us the international system is our fundamental object of study, and our understanding of the parts far outstrips our understanding of the whole. The field of astronomy would be embarrassed, and rightly so, if its most prominent academics could be grouped into “gravity theorists,” “orbit theorists,” “Jupiter theorists,” and so on, none of whom could give a coherent account of the workings of a solar system.