OUR UNIPOLAR WORLD IS PASSING INTO HISTORY, AS THE ECONOMIC CENTER OF gravity shifts eastward and southward and new centers of power emerge. Our international governance systems and institutions, constructed out of the ruins of World War II and the Great Depression, have been steadily lagging the steepening curve of change. Meanwhile, as the world struggles with the aftershocks of the global financial and economic crisis, terrorism, transnational crime and drug trafficking, climate change, food security and energy prices, the Arab Awakening, Japan's triple crises, failing and fragile states, the dangers of nuclear proliferation, and so forth, the virtues of multilateral cooperation are being rediscovered. Many see renewed merit in pooling national sovereignty in cooperative institutional arrangements. (1) At the same time, the preeminent power in the international system, the United States, burdened by debt, hobbled by internal divisions, newly conscious of its limits, led by a president whose formative years are more North-South than East-West, is itself putting greater stock in partnership and multilateral cooperation. (2) In response to this unprecedented pace and scope of change, old institutions are innovating and new forms and varieties of international cooperation are being called into being. Issues of legitimacy, accountability, social justice, and effectiveness are generating calls for change. Some, especially the emerging powers such as India, Brazil, and China would like to see a better representation of Southern values and interests in global summitry and in the major decisionmaking organs of the United Nations and Bretton Woods system. Western powers in the North privilege increased effectiveness. Still others, including the increasingly mobilized voices of civil society, want to see more accountability of the powerful to the less powerful, nationally and internationally, North and South. These continuing variances in what forms of cooperation are desirable pose formidable governance challenges. Such new challenges seem likely to require new forms of multilateral diplomacy--especially minilateralism--centered on institutional innovations such as the Group of 20 (G-20). Diplomacy will have to be sensitive to the needs and wishes of emerging economies and the interests of new global powers. This means less presumption on the part of the West, fewer decisions delivered from Mount Washington and additional hands on the global steering wheel and feet on the brakes and gas, as well. But as we argue, it will also require a greater sense of international civic duty on the part of the emerging powers. The response to the Libyan crisis of the claimants to permanent member status in the Security Council, who all put ideology and rhetorical posturing before protecting the innocent, is an indication of the distance still to be traveled. Brazil, Russia, India, China, and South Africa (BRICS) (3) seem more disposed to accept responsibility on economic as opposed to political issues on which some seem still wedded to old patterns of behavior. In global economic summitry in the G-20, China, Brazil, India, and other emerging economies are playing an increasingly important global role. Power sharing has to mean burden sharing if the reform process is to be effective, legitimate, and ultimately accountable. But burden sharing also has to mean benefit sharing. The Changing Meaning of Multilateralism At its core, the concept of multilateralism centers on the collectively agreed norms, rules, and principles that guide and govern interstate behavior. Multilateral institutions are all based on the principles of generalized reciprocity, in which states make common undertakings and agree to act cooperatively. (4) Multilateral arrangements typically cover four institutional domains: international orders like the Concert of Europe in the nineteenth century; international treaty regimes such as the Law of the Sea; international organizations, (5) notably the UN; and international negotiating processes and forums that generate institutional or outcomes such as the Ottawa landmines treaty and the International Criminal Court. …