Such measures attracted opposition. Henry Wallace, Roosevelt's vice president from 1941 to 1945 and presidential candidate in 1948, challenged the emerging "cold war" against the Soviet Union, charging that the United States was using "a predominance of force to intimidate the rest of mankind." Atomic scientists such as Albert Einstein and Leo Szilard eloquently warned of the perils of a nuclear arms race and established organizations and journals to challenge the political status quo. Journalists like Walter Lippmann and the radical I. F. Stone expressed their concern over the extensions of American power and responsibility into all parts of the world. Senators as diverse as the liberal Claude Pepper and "Mr. Conservative" Robert Taft feared the establishment of a military government. Vito Marcantonio, a Labor Party member of the House of Representatives, attacked business and military influences in Washington and the expansion of American capitalism into the developing world. Many liberals feared that the United States was abandoning its republican virtues, especially as the political repression associated with Senator Joseph McCarthy consumed the nation's political affairs in the 1950s.
African-American critics in particular challenged the intensified imperialism, as they saw it. Black leaders like W. E. B. Du Bois, Paul Robeson, and Harry Haywood believed it was dangerous, not to mention hypocritical, for the United States to spread its values and institutions abroad while maintaining a system of apartheid in its southern states. In particular, black spokespersons began to point out the common struggles of Africans trying to gain their national independence from colonial powers and of blacks in the United States seeking civil rights. Americans could hardly lead the "free world" by example, they argued, while maintaining legal segregation at home and endorsing continued colonization in Africa and other parts of the Third World. Although many mainstream black leaders supported the Cold War, hoping to parlay their loyalty to foreign policies into a commitment to act against racism at home, Du Bois, Robeson and others offered a more critical analysis, even invoking a Leninist critique of capitalist expansion and looking to the Soviet Union as an anti-imperialist model and champion of the rights of nonwhite peoples. Paul Robeson condemned Winston Churchill's "Iron Curtain" speech as a scheme for "Anglo-Saxon domination" of the world, and called for "united action of all democratic forces to achieve freedom for all colonial and subject peoples."
Views such as Robeson's, however, were not conventional wisdom, even in the black community, and most Americans accepted the new global role ushered in by the Cold War. Throughout the 1950s, then, the United States, without much dissent, intervened in a civil war in Korea, overthrew governments in Iran and Guatemala, offered economic and military support to military dictatorships throughout the globe, and continued to expand the Open Door. By the end of the decade, however, some Americans were uneasy with such hegemony, and various figures emerged to again challenge the U.S. empire. Cultural figures such as the beatniks condemned the conformity of Cold War life, the arms race, and the American denial of self-determination in other lands. More powerfully, and perhaps surprisingly, President Dwight Eisenhower, as he was leaving office in 1961, warned against "the acquisition of unwarranted influence … by the military-industrial complex. The potential for the disastrous rise of misplaced power still exists." Such thoughts may have remained a novelty in the 1960s, but U.S. intervention in Vietnam, still limited as Eisenhower left office, would mushroom in the coming years and give rise to a mass antiwar movement that would also question what critics saw as America's imperial behavior overseas and the military-industrial complex at home.
As in the 1840s and 1890s, many Americans in the 1960s opposed U.S. intervention in a foreign war and developed a larger anti-imperialist critique as a result of their challenge to the conflict at hand. Even before the major decisions to commit advisers, airpower, and combat forces, and essentially "Americanize" the Vietnam War, there was evident concern over the growing U.S. role in the world. Movements calling for an end to the arms race, peace with the Soviet Union, normal relations with Cuba, and recognition of the People's Republic of China, for instance, were in existence during the presidency of John F. Kennedy, and the Cold War consensus on an aggressive foreign policy, though still noticeable, was being questioned in some quarters. Vietnam accelerated that process, however, and brought about the greatest domestic challenge to American involvement abroad in the twentieth century.
By 1964, as the United States began to conduct air attacks against the National Liberation Front in Vietnam, peace activists, professors, and students were beginning to challenge the growing American role in Indochina and the larger foreign policy context of the cold war. Scholars such as the linguist Noam Chomsky, the historian William Appleman Williams, and the political scientist Hans Morgenthau participated in "teach-ins" on Vietnam, giving rise to a national movement on college campuses and serving as a foundation for the antiwar movement. The Students for a Democratic Society, the largest radical student group of the period, held the first antiwar rally in 1964, and its adherents not only scored intervention in Vietnam but also offered a comprehensive analysis of the leaders of the American "empire," which, they charged, denied self-determination to Third World nations, intervened on behalf of corporate interests, and betrayed American principles. African Americans, engaged in an epic struggle for civil rights, added, as had Du Bois and Robeson earlier, that the United States had assumed the position of a white imperial power suppressing the yearnings for freedom of nonwhite peoples, whether in Indochina or below the Mason-Dixon Line. Martin Luther King, Jr., Nobel Peace Prize winner and civil rights leader, went so far as to call the United States "the greatest purveyor of violence in the world today," while the militant Black Panther Party called on African Americans to refuse to join the military or support U.S. intervention and openly sympathized with Third World revolutionary and anti-imperialist movements.
Politicians entered the debate as well, as they had during the League of Nations fight after World War I. Senators J. William Fulbright, George McGovern, Ernest Gruening, Wayne Morse, Mark Hatfield, Frank Church, and others were, like the progressives of the 1920s, anti-imperialist and internationalist. Fulbright, like Borah, chaired the Senate Committee on Foreign Relations and opposed the policies of the president of his own party. The senator from Arkansas believed that America had "betrayed its own past and its own promise … of free men building an example for the world. Now … it sees a nation that seemed to represent something new and hopeful reverting to the vanity of past empires."
Similar opinions were held by a significant number of Americans, including religious leaders, businessmen, and even military officials. Following in the tradition of Smedley Butler, former Marine Commandant David Shoup blasted not only the war but also the foundations of U.S. foreign policy. "I believe that if we had and would keep our dirty, bloody, dollar-crooked fingers out of the business of these nations so full of depressed, exploited people," he said in 1966, "they will arrive at a solution of their own. That they design and want. That they fight and work for. [Not one] crammed down their throats by Americans." Shoup's views, bluntly expressed, were shared by a significant number of Americans by the late 1960s and 1970s. Millions demonstrated publicly against the war and also called for a new, noninterventionist foreign policy. "Dove" senators tried to pass legislation to limit the war and, after U.S. withdrawal from Vietnam in 1973, enacted the War Powers Act to restrict the power of the president to commit U.S. forces abroad, a measure that was principally a response to the "imperial" presidency of Richard Nixon, who had waged war without authorization in Cambodia and Laos and was responsible for the Watergate crisis at home. By the mid-1970s, the United States seemed less prone to intervene in world affairs, a condition derided as the "Vietnam syndrome" by conservative critics but hailed as an anti-imperialist triumph by progressive and inter-nationalist forces.
Such restraint, however, was short-lived; the Carter and Reagan administrations began to ratchet up the Cold War, increasing military spending, taking a more bellicose approach to the Soviet Union after the détente of the 1970s, and asserting American imperium in Central America and elsewhere. Millions of citizens, often invoking the legacy of Vietnam, challenged such policies as violations of national and international laws and of American values. Amid the Iran-contra scandal, they pointed out the similarities between the imperial presidencies of Richard Nixon and Ronald Reagan. Still, the 1980s and early 1990s were not periods of great anti-imperial activity. That would change dramatically, however, by the later 1990s as Americans had a vital role in a global coalition that was challenging the world's economic structure. In some measure, conservatives such as Pat Buchanan and Ross Perot, maverick presidential candidates in 1992 and 1996, used anti-imperial and nativist themes to sound the alarms about the new global economy. Sounding like progressives in the 1890s or isolationists after World War I, they believed that transnational corporations were moving abroad to find cheaper labor, thus causing American workers to lose jobs, and that the government and business elite was more interested in extending its interests abroad than in taking care of its citizens at home. Ironically, they even called for an end to U.S. sanctions against enemy states such as Iraq and Cuba, governments for which they held little love, because such economic warfare was damaging the people of those lands and not helping to oust Saddam Hussein and Fidel Castro. The United States was "a republic, not an empire," Buchanan often reminded Americans throughout the 1990s.
By the later part of that decade—with many major powers establishing regional and world economic groups such as the European Union, signatories of the North American Free Trade Agreement, and the World Trade Organization— anti-imperialists went on the offensive. Although such institutions had usually existed with little fanfare or opposition, critics such as Chomsky, the longtime consumer advocate Ralph Nader, and the anti-globalization activist Kevin Danaher emerged to attack what they considered a new form of global empire, with the United States as hegemon. From 1999 to 2001, when environmentalists, union members, student activists, anarchists, and other forces disrupted meetings of the World Trade Organization in Seattle, of the World Bank in Washington, D.C., and of the Free Trade Area of the Americas in Quebec, the lines were drawn in this new round in the global contest between the great powers and the forces of anti-imperialism.
As critics of American power, expansion, or empire entered the twenty-first century, they were using many of the same arguments that George Washington, John Quincy Adams, Mark Twain, William Borah, and J. William Fulbright put forth in earlier periods. Broadly defined to mean the aggressive use of power, the denial of self-determination abroad, militarism, or actions inconsistent with a republican form of government, American imperialism has a long tradition, but so does its anti-imperial counterpoint. Clearly, anti-imperialists, isolationists, doves, and others opposed to the excessive use of power or the extension of U.S. influence have been on the defensive as American leaders have tallied up an impressive array of territorial holdings, military interventions, proxy governments, and economic opportunities. One can ponder, however, how much more expansive the reach of American power or the extent of American militarism would have been without critics at home challenging the establishment and augmentation of "empire" at all steps along the way.
"The price of empire," J. William Fulbright remarked during the Vietnam War, "is America's soul, and that price is too high." Those words could just as easily have been uttered by John Quincy Adams at the turn of the nineteenth century. As America goes abroad in the future, in search of markets, bases, or even monsters to slay, one can be reasonably certain that there will be significant forces at home questioning and protesting against such extension of U.S. power, as there have been for more than two centuries.