An approach to international trade, the monetary system, international disarmament and security, or the environment, based on the idea that if international cooperative regimes for the management of conflicts of interest are to be effective, they must represent a broad and sustainable consensus among the states of the international system. Multilateralism therefore lends itself to issues where clear common interests in the international community are identifiable. It should be thought of in contrast to strictly unilateral or bilateral initiatives.
Many recognized that during the inter-war years the exclusionary nature of bilateral bargains and the frequent resort to unilateral action had contributed to the breakdown of the international economy and the onset of war. Multilateralism therefore became the norm in such post-war agreements as Bretton Woods, the World Trade Organization/GATT, the United Nations, and, more recently, accords on the ozone layer or global warming. On questions of national security states have often proved reticent to accept the constraints of multilateral diplomacy, but there have been notable examples of multilateral action through the UN in the post-war period.
Global multilateralism has, however, been challenged, particularly with respect to trade, by emerging regional arrangements such as the European Union or NAFTA, not in themselves incompatible with larger multilateral accords. More seriously, the original sponsor of post-war multilateralism in economic regimes, the United States, has turned towards unilateral action and bilateral confrontation in trade and other negotiations as a result of frustration with the intricacies of consensus-building in a multilateral forum. As the most powerful member of the international community by far, the United States has the least to lose from a defection away from multilateralism, and the weakest nations the most, but the cost for all would be high.
In disarmament and arms control, important changes have also taken place in the post-war period. Initially it was felt that effective control of arms would require an ongoing multilateral forum in the context of the United Nations. As the nuclear arms race between the United States and the USSR emerged, however, it became clear that the two superpowers were unwilling to cede the issue of arms control policy to multilateral discussions. Despite consistent multilateral efforts, including the Partial Test Ban Treaty of 1963, the Non-Proliferation Treaty of 1967, and the chemical and biological weapons agreement of 1971, key arms control measures depended largely on bilateral superpower accords outside UN processes. Even the multilateral success stories rested on superpower cooperation.
The US-Soviet SALT I agreement of 1972, coupled with the Anti-Ballistic Missile Treaty, was followed by SALT II in 1979. These opened the door to further multilateral agreements, especially with the changes in Soviet foreign policy under Mikhail Gorbachev that led to the end of the Cold War. This quickly resulted in the Conventional Forces in Europe agreement of 1990 between NATO and Warsaw Pact members, as well as additional bilateral nuclear arms control agreements such as the Intermediate Nuclear Forces (INF) Treaty of 1987 and START in July 1991. With the collapse of the Soviet Union, even nuclear arms control matters are now essentially multilateral because offshoots of the former USSR (e.g. Ukraine, Kazakhstan) possess nuclear weapons that were once Soviet property. These smaller states have recently agreed (Ukraine in 1994) to transfer their arms to the Russian Federation.
Multilateral agreements more often than not are underpinned by great-power understandings. The conclusion of the WTO Uruguay Round in December 1993 depended on prior EU-US agreements. But the powerful can wreck as well as underpin multilateral agreements. The arrival of a new administration in Washington in 2001 under President George W. Bush has called many aspects of multilateral cooperation into serious doubt, including nuclear arms control treaties and environmental protocols to which the US is a signatory. Without US support the future of multilateral cooperation would become uncertain.
— Geoffrey R. D. Underhill




