A principal set of core elements in the American ideology that affects feelings about international law's role in U.S. foreign policy originates from a sense of exceptionalism, often expressed as self-virtuosity. That is, Americans seem to be self-confident to the degree that they and their political culture are admired and thought special by the rest of the world. To early Americans the New World was a gift from God, which settlers transformed out of wilderness into the most prosperous and advanced society in history. Traditional perceptions of history reinforce this conclusion: Americans conquered native, "uncivilized" peoples, survived a brutal civil war, moved westward and secured the continent, established a country founded on private, free-enterprise capitalism and democratic principles, rescued Europe from the evils of nazism in World War II, and saved the world from communist domination in the four decades thereafter. In the American mind, these profound accomplishments make the United States the envy of the world and correspondingly reinforce the sense of being uniquely special. Americans thus are prone to view the United States as having evolved into an exceptional country that is not merely different from, but actually superior to, all other states.
Exceptionalists admit that the United States has a certain moral responsibility for the fate of people living in other countries. As such, they advocate international activism and interventionism in a wide variety of global situations. They do not concede to any clear, universally accepted international code of foreign policy behavior. Their chief belief is that the United States should advance principally American values in its foreign policy.
Belief in American exceptionalism has sometimes bred U.S. unilateralism in foreign affairs. That is, integral to Americans' belief that their country's experience has produced the best social and political order in history is the predilection of the United States to act alone in addressing foreign concerns. This go-it-alone tendency in U.S. foreign policy represents the rejection of a balance-of-power approach for promoting national security in international relations. Given the geography and natural assets of the United States, national security was once largely assumed, making efforts at multilateral collaboration unnecessary. After World War II, the rise of the United States to superpower status exaggerated its self-perceived virtuosity in world affairs, which generated more acts of unilateralism in its foreign relations and international law attitudes.
Another facet of American self-virtuosity arises in the tendency to engage in messianism abroad. American foreign policy sometimes takes up crusadelike causes for ends that are perceived as just and noble. U.S. policymakers conclude that they must bring the benefits of American ideals and institutions to other, less fortunate, peoples. Such feelings blend the traits of the American self-image of political, moral, and ideological superiority to produce within the American political culture a tendency to engage in messianic campaigns. There emerges a missionary-like compulsion in U.S. foreign policy ambitions to recreate the world in the American image, to establish models of governance grounded in American values and democratic institutions, by force if necessary. Such attitudes can foster a sense of paternalism. More ominously, they breed resentment from other societies who see the United States as attempting to impose its cultural values and political lifestyle upon them. In the extreme, such a doctrine of internationalized manifest destiny can become the political rationalization for unlawful U.S. intervention. Witness, during the second half of the twentieth century, U.S. involvement in Iran (1953), Guatemala (1954), Cuba (1961), the Dominican Republic (1965), Chile (1973), Nicaragua (1981–1984), Grenada (1983), Panama (1989), and Serbia (Kosovo) (2000).
The clearest historical statement of American unilateralism remains the Monroe Doctrine in 1823. This declaration by President James Monroe came in reaction to U.S. concern over the possibility of European interference into affairs of newly independent Latin American countries. The doctrine proclaimed that the United States would not tolerate European intervention into the Western Hemisphere, and, in return, the United States pledged not to interfere in European affairs. The Roosevelt Corollary, articulated by President Theodore Roosevelt in his annual message to Congress on 6 December 1904, expanded the scope of the doctrine by making the United States the self-appointed policeman of the Western Hemisphere, thereby providing a unilateral justification for increased intervention into the affairs of Latin American countries.
Important to realize is that neither the Monroe Doctrine nor its Roosevelt Corollary drew validity from any U.S. legislative pronouncement, nor from any international treaty instrument. Nor was the reach of jurisdiction or application of either doctrine ever precisely defined by specific law or fiat. Indeed, both doctrines were applied historically on an ad hoc basis, in circumstances defined only by perceptions of U.S. policymakers, to explain the rationale for interventionist actions. From 1850 to 1935, both doctrines were held out as pillars of U.S. foreign policy and were invoked periodically to justify unilateral interventions taken in the name of defending the Americas from European intrusions. For example, in the first three decades of the twentieth century, the United States intervened militarily on some sixty occasions in several small Caribbean and Central American states. In all these cases, little diplomatic consideration or formal concern was expressed by the U.S. government about the international legal implications of these interventions or the critical attitudes of other states.
Although largely repudiated with the rise of Pan Americanism during the administration of President Franklin Roosevelt during the 1930s, the legacy of the Monroe Doctrine persisted in modern times. Involvement of the Central Intelligence Agency in overthrowing the Arbenz government in Guatemala in 1954 and the Allende government in Chile in 1973, U.S. complicity in the 1961 Bay of Pigs invasion and in blockading Cuba during the missile crisis in 1962, the 1965 invasion of the Dominican Republic, the 1983 invasion of Grenada, and the 1989 invasion of Panama attest to the continued influence of U.S. unilateralist behavior in the Western Hemisphere.