The article focus on how relevant, and under what conditions, multilateral relationships are in unipolar systems and, more specifically, if those can change the behavior of the sole pole of the system. First, we distinguish unipolar from strictly hegemonic systems. Then, the behavior of that single pole is established as the crucial parameter of international politics in any unipolar system. After that, the article establishes: the theoretical Grand-Strategic Goals of a Unipolar Power; the theoretical Grand Strategy of any Unipolar Power - which would enable it to achieve those Grand-Strategic Goals; and the theoretical Policy of Grand-Strategic Support - that addresses the means by which to carry that Grand Strategy. This will enable us to address four questions: (a) what is the utility (in the economist’s sense) of multilateral relationships from the point-of-view of a Unipolar Power; (b) what is the bargaining power vis-à-vis the Unipolar Power of the many international actors that are part of those relationships; (c) what is the utility of critical allies to a Unipolar Power; (d) the bargaining power of those critical allies vis-à-vis a Unipolar Power. Knowing this, not only a unipolar power might better assess its own behavior and options, but other international actors might better calibrate if, when and how they might resist some policy options by a unipolar power, should they want to.
International Relations Theory; Unipolarity; Offensive Realism; International Organizations; Multilateralism; Alliances