Keohane and Nye say that "Contemporary world politics is not a seamless web; it is a tapestry of diverse relationships. In such a world, one model cannot explain all situations. The secret of understanding lies in knowing which approach or combinations of approaches to use in analyzing a situation". In that phrase we can find the purpose of this book: to give the reader some analytical tools that will help him to comprehend our world.
The authors say that neither the traditionalist vision nor the modernist vision is nowadays adequate to interpret our world, due to the fact that there is an ever- growing and multidimensional interdependence. Their task is to point out to us the situations in which the assumptions that characterize each vision should be applied, to offer good predictions and satisfying answers. In their words, "to provide a means of distilling and blending the wisdom in both positions by developing a coherent theoretical framework for the political analysis of interdependence".
In "Power and interdependence", you will be introduced to quite a few interesting concepts, starting by what does interdependence mean, and the differences between interdependence and dependence. Each definition is accompanied by several examples, that make the concepts easier to grasp.
I found especially interesting the way in which Keohane and Nye explained the role of power in interdependence, by distinguishing between two dimensions of interdependence: sensitivity and vulnerability. Sensitivity has to do with how much a country is affected by the policies of another country before reacting to those changes (the key assumption here is that the framework isn't changed). On the other hand, vulnerability takes into account how well and quickly a country can react to the changes in policies produced by other states, and has to do with the existence of alternatives (the assumption here is that the framework is changed). The authors illustrate this distinction with examples taken from history, and conclude that sensitivity interdependence is not as important as vulnerability interdependence from the point of view of providing power resources to actors.
Another interesting feature of this book is that the authors compare two ideal types: realism and one that they constructed, complex interdependence. None of these ideal types reflects reality exactly, but they help to understand what happens, because most situations fall between these two extremes.
They say that the realist ideal type involves three basic assumptions. To start with, states (rational and coherent units) are the more important actors in world politics, and interstate channels are the norm. Secondly, force is the more effective instrument of policy, even when there are others. Lastly, there is a hierarchy of issues, and the one that dominates is military security.
In contrast to that, the ideal type of complex interdependence has rather different assumptions. To begin with, the state is not the only important unit, and there are many channels that connect societies (not only interstate channels, but also transgovernmental and transnational ones). Also, there isn't a hierarchy among issues, and it is more difficult to distinguish between domestic and foreign policy. Finally, "military interdependence is not used by governments towards other governments within the region, or on the issues, when complex interdependence prevails". By that, I think that the authors mean the relationships between developed countries (North/North relationships). In complex interdependence, military force loses a lot (but not all) of its importance, mainly because using force can have negative effects on non security goals.
Other themes that you will find in "Power and interdependence" but that I won't explain now (this review is already too long!!) are linkage strategies (different for strong and weak states) and the role of International Organizations, agenda setting, international regime changes, the relationships between USA and Canada and Australia, and USA, its leadership and complex interdependence.
Keohane and Nye try to explain us how our world is changing (and yes, they had already observed those changes when this book was first published, many years ago), and highlight many times throughout the pages of this book that they believe that different frameworks are needed for different situations, and that old contributions are as worthy as new ones. It is essential, however, to know when to use each one, and when we must combine them, in order to grasp the various situations. Due to the fact that they repeat the same thing many times, the reader is highly unlikely to forget it. To me that is great, because it is an idea we need to remember.
"Power and interdependence" is neither overly easy to read, nor too difficult. However, if you are tenacious you will be rewarded, because you will end up having another tool with which to understand the world. All in all, strongly recommended :)