Few people study world politics for purely intellectual reasons. Other disciplines, even in the social sciences, offer better prospects for intellectual rigor and cumulative progress in solving well-defined problems. Students of world politics therefore face inherent limitations to scientific prediction and to fully satisfactory explanation—limitations that we are unlikely ever to overcome. The justification for spending one's professional life studying world politics cannot, therefore, be a purely scientific one. On the contrary, it is profoundly normative. Further work on the international political economy ran the risk of being only a set of extended footnotes to Power and lnterdevendence. Understanding the right question on which to focus is often the most difficult part of a research project in international politics. Not all cooperation has worthy purposes—governments often cooperate to make war, to exploit others, and to conceal the effects of their depredations.