One of the meanings of the worldwide restlessness that marked the 1960s may well be that the notable social discipline characteristic of the populations of industrialized countries in the first century of the Industrial Age was breaking down. If so, a fundamental shift in social organization may underlie the contrast between the unity with which the United States fought the two world wars and the reversion to major dissent and internal conflict in the Korean and Vietnam wars. But more immediate explanations for the contrast readily present themselves. The most frequently voiced explanation is that the world wars fitted much better than the more recent wars the traditional American image of the nature of war. From the colonists' first struggles with the Indians, in which each side fought for the very survival of its culture, this argument goes, Americans came to regard wars as total struggles for absolute victory or defeat. The very aversion to war and the military that was so much a part of American tradition implied that when the nation went to war, it must be under the most extraordinary circumstances, and that so immoral an instrument must be employed only against such moral enormities as demanded absolute destruction. The American Civil War reinforced these preconceptions as the North fought for and achieved complete victory over the Confederacy. The argument concludes that after such a history, Americans could well sustain their unity against the Axis Powers during World War II, but they could not readily accept a limited war such as the Korean War, in which negotiations with the enemy to bargain for objectives far short of his destruction accompanied the very fighting of the war.
Allowing for some oversimplification—not every American war had been fought for the enemy's destruction, as witness the conflicts of 1846–1848 and 1898—such an explanation captures much of the American attitude toward war and goes far to account for the frustrations of the Korean War. Dissent against the Korean War also was much encouraged by a peculiarly uneasy political atmosphere troubling the United States in 1950 even before the war began. World War II had produced not a satisfactory peace but a Cold War with communism and the Soviet Union, in which the United States government held out the prospect of no more triumphant an outcome than containment. So low an expectation was itself a drastic departure from popular expectations of what America might accomplish in the world. Moreover, from 1945 to 1950 the containment policy did not even produce a satisfactory restriction of communism. China, with all its historic attractions to the American imagination, fell to the communists. Then there broke out the prolonged, costly, and militarily stalemated war in remote Korea, a war which itself could be perceived as springing from the mistakes of Harry S. Truman, whose Democratic administration had allowed China to be "lost" and had then supposedly invited communist attack on South Korea by excluding that country from America's publicly proclaimed Pacific defense perimeter.
During the Korean War the opposition party, the Republicans, did not revert to the risks of outright partisan opposition, although they came close to that in such statements as Senator Taft's denunciation of the war as "an unnecessary war … begun by President Truman without the slightest authority from Congress or the people." Here Taft touched also on another source of public dissatisfaction in the post-1945 limited wars, the unwillingness of presidents for various reasons to ask Congress to declare war. In such puzzling circumstances of undeclared war for limited but not clearly defined objects, it was not surprising that Republican objections came to focus on the theme that the war should either be fought to win or be terminated. This theme linked the Republicans with General Douglas MacArthur, the Far East commander whom President Truman felt obliged to relieve because of his insubordinate public calls for extension of the war in pursuit of "War's very object … victory."
The upshot of MacArthur's activities was the dramatic Truman-MacArthur crisis; but given the anomalies of the Korean War in terms of the American tradition of war, Korea would have provoked much the same partisan and popular discontent even if there had been nothing like that particular eruption. The concept of limited war was difficult for the sponsoring administration itself to master. The theorizing that was to make limited war a familiar conception at least to foreign policy and strategy intellectuals during the next decade still lay in the future. The Truman administration kept the Korean War limited not out of a sophisticated understanding of the conception but largely because of a misapprehension, namely that the war was a communist feint to divert American attention in preparation for a major Soviet offensive in Europe, and that, accordingly, American military resources must remain as much as possible concentrated in Europe and the United States. After China entered the war and destroyed the possibility of using the war to reunite all of Korea, the Truman administration lost its own enthusiasm for prosecuting the war, such as it had been able to summon up, and the administration became so eager for peace that it spared the enemy most military pressure as soon as it announced a disposition to negotiate. In these circumstances the negotiations dragged on inconclusively until the inauguration of a new government in Washington. With the very sponsors of the war so vague about its nature and objectives, so unskillful in its management, and so lacking in conviction that it was worth fighting, it is little wonder that public discontent with the prolonged bloodletting and the absence of clear military success made the Democrats extremely vulnerable in the elections of 1952. The electorate responded to Republican criticism of every aspect of the conduct of the war, and especially to the Republican candidate General Dwight D. Eisenhower's promise that somehow he would end it. With the help of the East-West thaw that followed the fortuitous death of Soviet Premier Josef Stalin, President Eisenhower did end the war.
Dissent in the Vietnam War seemed to be still deeper and more widespread. Dissent certainly became a more conspicuous feature of the public scene, expressing itself in mass protest marches, demonstrations, and displays of civil disobedience. Public opinion polls indicate, however, that opposition to the Vietnam War grew stronger than opposition to the Korean War only after the Vietnam War had surpassed the Korean War in duration and in American casualties. The conspicuous public displays of dissent reflected not so much a greater opposition to the war in Vietnam than the war in Korea, but rather a shift in liberal opinion. Except for the extreme left wing, liberals had usually supported the Korean War as part of the staunch anticommunism that tended to mark their reaction to Stalinist Russia. By the 1960s, a less intransigent Soviet Union, the disruption of virtually all appearances of a monolithic international communism, and a rethinking of Cold War postulates in a more relaxed international atmosphere than that of the Truman years made liberals much less willing to support another war against a small Asian communist state than they had been in 1950–1953, especially when the Asian regime being supported by the United States was a distasteful blend of dictatorship and chaos. The conspicuousness of dissent against the Vietnam War was largely a product of the defection of many of the liberals from the foreign policy coalition of the establishment, because this group was an especially articulate one, in direct line of descent from the literary and academic dissenters against suppression of the Filipino insurrection. The conspicuousness of dissent against the Vietnam War was also much enhanced by employment of the methods of dramatizing dissent that liberals had learned from association with the civil rights movement of the late 1950s and early 1960s. Measured against the apparent volume and the new tactics of dissent, the tolerance of the government for controversy displayed an advance over World War I, despite conspiracy trials directed against dissenters and the illegal methods of attempting to discredit Daniel Ellsberg, who leaked the so-called Pentagon Papers to the press.
The liberal defection during the Vietnam War from the coalition that had supported the Truman administration during the Korean War also reinforced the moralistic quality that dissent from the Vietnam War shared with dissent during the Mexican War and the Filipino insurrection. The liberal protest against the Vietnam War was another moral protest against an allegedly aggressive onslaught by the great and powerful United States against a weak and ill-armed adversary that was said to be seeking only the self-determination that America's own Declaration of Independence championed. Like dissenters during the Mexican War and the Filipino insurrection, liberal protesters against the Vietnam War charged that the war was betraying the highest ideals of the United States itself. Some of the more horrifying military expressions of modern technology, such as defoliation techniques and napalm, combined with an indiscriminate use of aerial and artillery bombardment by the American forces in Vietnam, gave special intensity to this moral protest.
Yet public dissent against the Vietnam War was not primarily moralistic. The conspicuous character of left-wing protest demonstrations against the war gave a misleading impression of the degree and the nature of the unpopularity of the war as compared with the Korean War. The left-wing protesters, especially the young among them, through the very tactics that made their protests conspicuous, antagonized moderate and conservative citizens. At any rate, the larger public discontent—including that discontent that most directly contributed to the electoral defeat of the original Democratic sponsors of the war and the triumph of their Republican opponents in 1968, much on the model of 1952—was not a moralistic dissent. It was again an expediential discontent that the issues of the war were puzzling in contrast to the great crusades of the world wars and that the Vietnam War was not being won.