Public attitudes in the United States toward the utility of international law have shifted with its government's perceptions of how the United States best fits into the world scene. At the same time, government officials do not agree to international legal rules in a political void—domestic political considerations and national interests figure prominently, and often preeminently, in negotiating legal instruments. Historically, the propensity of U.S. government officials for creating legal rules was caught in the tension between two opposing policy approaches—isolationism and internationalism. Up until 1940 these approaches were more or less cyclical throughout American history. Since then the East-West ideological rivalry of the Cold War, escalating international economic interdependence, and ever-increasing technological globalization have combined to render the internationalist approach politically, commercially, and legally imperative for the United States.
Isolationism reflects the belief that the United States should avoid getting involved in the political affairs of other states. This rejection of foreign political involvement was not meant to imply that the United States should ignore the rest of the world. Indeed, diplomatic and commercial contacts were critical for the United States as it developed throughout the nineteenth and early twentieth centuries. In these respects, international legal rules and multilateral instruments assumed cardinal importance in rendering American foreign policy practical and effective. Instead, from the isolationist perspective, American national interests are best served by withdrawing from the rest of the world, or at least remaining detached from events elsewhere. In this regard, international legal rules play only a minimal role. Less international involvement abroad results in less interest in world affairs and fosters the perception that the United States has little need to be bound by international law.
Isolationism draws its inspiration from George Washington's Farewell Address of 1796, in which he admonished Americans to "steer clear of permanent alliance with any portion of the foreign world." This tendency to avoid foreign involvement was fueled by the fact that, save for the War of 1812, the United States was never physically endangered by foreign military attack, and a sense of physical security from the threat of foreign intervention prevailed. Later, the horrors of the Civil War fostered a less militaristic attitude within the American political culture. When combined, these attitudes contributed to the isolationist impulse and a relative indifference to international legal concerns. Among the major isolationist foreign policy decisions that heavily impacted on principles of international law are the Monroe Doctrine (1823), the refusal to join the League of Nations (by the U.S. Senate's rejection of the Treaty of Versailles in 1919), the neutrality laws of the 1930s, and the legacy of the Vietnam syndrome, that is, the reluctance to commit American troops abroad.
The internationalist perspective sees the protection and promotion of U.S. national interests through pursuit of a legally based, activist, global foreign policy. Internationalists argue that the United States cannot escape the world. Events in other places inevitably encroach upon U.S. interests, and policy rooted in the retreat from global involvement is self-defeating. Thus, the United States has a stake in the general nature of the international system, and its government must be willing to become actively involved in world affairs on a regular basis. To bolster this contention, internationalists point to the Great Depression of the 1930s, the rise of Hitler in Europe, the outbreak of World War II, and the expansion of communism in the war's aftermath. Hence, the United States must be involved in world affairs. To this end, international law provides proven conduits for integrating U.S. national interests into constructive foreign policy opportunities. American national interests are best served by remaining active internationally and by negotiating legal rules that promote foreign policy goals as they foster international order. Evidence that internationalism best serves U.S. national interests is seen in the preeminent place of the United States since 1945 in establishing the United Nations, the North Atlantic Treaty Organization (NATO), and many other international organizations; in promoting the Marshall Plan and the Helsinki Human Rights Agreement; in U.S. involvement in armed conflicts in Korea, Vietnam, the Persian Gulf, Bosnia, and Kosovo; and in vigorous support of a massive expansion of U.S. international trade relations. In all of these areas, the ways in which the United States employed international legal rules proved critical for implementing its foreign policy in ways acceptable to international society.
The war in Vietnam frayed American confidence about internationalism in general and the containment doctrine in particular. The tremendous human, financial, and political costs traumatized the American people, gave rise to a domestic antiwar movement, and undermined the faith of Americans in their government. More than 58,000 American lives were lost, and four million Vietnamese on both sides were killed or injured. Over eleven years the war cost the United States approximately $150 billion to fight and lose. Consequently, since 1975 American attitudes have been ambivalent toward activist internationalism. On the one hand, the realization persists that as the world's only superpower, the United States retains a special responsibility for maintaining international peace and security. But, on the other hand, the American people are profoundly reluctant to support long-term commitments of American blood and treasure abroad to defend other states, especially those with little strategic value to the United States. American government officials therefore are wary about sending U.S. forces abroad and have done so only in selected cases. They are fully aware that a high political price can be incurred for American soldiers coming home in body bags—namely, defeat in the next general election.
Isolationism and internationalism have both shaped the course of American foreign policy and determined the relative degree of importance that international law has assumed in policy formulation. Both approaches are joined in the conviction that international law should be used to serve and protect the institutions and ideals of the American experience. The approaches differ, however, on how to achieve these national ambitions. Isolationism aims to insulate the American experience from the corruption of foreign influences and protect U.S. sovereignty from burdensome international commitments. The isolationist approach attributes little utility to international law, except insofar as it segregates the United States from extraterritorial commitments and facilitates the government's foreign relations to secure needed resources and sustain trade relations. Conversely, internationalism works to attain U.S. policy goals by promoting a more stable global environment for the United States, which opens the door to foreign opportunities to fulfill American political, economic, and legal interests. To these internationalist ends, international law assumes a more fundamental, more comprehensive place in U.S. foreign policy. International legal rules become channels for closer, more regularized international contact as well as regulatory standards that encourage such cooperation. Regardless of the approach taken, consideration of and regard for international legal rules remain important in the process and formulation of American foreign policy.