April 30, 2025 marked the 50^th anniversary of the fall of Saigon and America’s ultimate defeat in the Vietnam War. U.S. involvement in Vietnam stretched back to the Truman administration which provided aid to the post–World War II French government in its effort to maintain France’s imperial possessions in Southeast Asia. When France was defeated at the Battle of Dien Bien Phu in May 1954, the United States stepped into the power vacuum in an effort to prevent the communists from controlling all of Vietnam.

The Eisenhower administration provided military and financial assistance to the non-communist government in the southern half of the country and eventually sent military advisers as well as covert operators to support the new government of South Vietnam. Some U.S. conservatives like Vice President Richard Nixon had suggested greater American military involvement to help France maintain its imperial presence, but Eisenhower, in the wake of the divisive Korean War, refused to get the U.S. directly involved in combat operations in Vietnam.

Eisenhower, who publicly worried about “dominoes” falling in Indochina if the communists succeeded in conquering all of Vietnam, was a conservative realist in foreign policy, and his reluctance to wage a ground war in the jungles of Southeast Asia was, as events later showed, prudent and wise. Eisenhower understood the limits of American power and the danger of imperial overstretch that had undermined the French and British colonial empires.

Unfortunately, no such prudence and wisdom affected the decision-making of the “best and the brightest” of the Kennedy-Johnson administrations, which gradually expanded American military involvement in Vietnam, eventually transforming the war into America’s war. This, despite warnings from the likes of Eisenhower and General Douglas MacArthur to avoid a land war in Asia. Kennedy and Johnson were intent on not “losing” Vietnam the way Truman and the Democrats had been accused of losing China. The accusation about losing China happened to be true, but China was a potential geopolitical giant (it is one today); Vietnam was not. Years later Richard Nixon as president understood the relative importance of Vietnam and China, which is why he was willing to negotiate an imperfect retreat from Vietnam as part of his triangular diplomacy with China and Russia.

The Vietnam War became an unmitigated military and political quagmire because the Kennedy-Johnson administrations were staffed with liberal internationalists who believed the Wilsonian nonsense written by Ted Sorensen and uttered by President Kennedy in his inaugural address about bearing any burden and paying any price to assure the survival of liberty. In Vietnam, the price was paid and the burden was borne by the hundreds of thousands of American servicemen who fought, in the war, including more than 58,000 who died.

Many conservatives supported the Vietnam War because it was a war against communism and a regime supplied and funded by the Soviet Union and Communist China. And even the few conservative realists who supported the war, like James Burnham and General Curtis LeMay, did so with the assumption that the United States would seek victory instead of stalemate. As early as 1962, Burnham wrote in National Review that waging war in Vietnam would be “senseless butchery” unless we fought to win, which would mean taking the war to Hanoi and even China. Burnham wrote that we should fight to win or get out. The Kennedy-Johnson administrations did neither, relying on “graduated response” and “body counts” to determine victory or defeat, forgetting Clausewitz’s dictum about the political nature of war.

The American left opposed the war mainly because its members viewed America as the aggressor in the conflict, while praising the revolutionary regime of Ho Chi Minh. Some of the left’s “political pilgrims,” to borrow Paul Hollander’s insightful phrase, traveled to the promised land of North Vietnam to express their solidarity against American imperialism, while many more took to the streets of America to protest America’s “illegal” and “immoral” war. Gradually, the anti-Vietnam War left took over control of the Democratic Party, and many of those who helped create the Vietnam quagmire, like Robert F. Kennedy, joined the anti-war movement for political reasons.

There were a few conservative realists who, to their credit, opposed the Vietnam War early on for practical, not ideological, reasons. Hans Morgenthau, the author of Politics Among Nations (1948), threw cold water on the notion promoted by the “best and the brightest” in Washington that the fate of Asia and the global balance of power was at stake in Vietnam:

If the stakes in Vietnam are as high as the supporters of the war make them out to be, if indeed the credibility of the United States and its prestige as a great power are at issue, if perhaps even the fate of Asia and of the non-Communist world at large will be decided in Vietnam, then the risk of a direct military confrontation with China and the Soviet Union is worth taking. If, on the other hand, the stakes are minor or as mythological as the commitment to a Saigon government and the eagerness of the people of South Vietnam to be defended by us have already proved to be, then the risks we have been taking have been out of all proportion to the interests involved.

Morgenthau acknowledged that we had placed our credibility at issue in Vietnam, but that didn’t mean our interests justified doing so, and prudent realism counseled cutting our losses before they got worse. Morgenthau wrote this in May 1966. The next month, Morgenthau criticized President Johnson and his national security team for “seeking a victory that cannot be obtained with the means employed” and for promoting the idea that increasing those means will allow us to “achieve the ever elusive end.” American policy, Morgenthau wrote in another article, “must be to avoid getting more deeply involved in [the war] and to extricate ourselves from it while minimizing our losses.” In short, for Morgenthau, there was no vital American interest at stake in Vietnam, therefore we shouldn’t waste our limited resources and American lives there.

In an essay in Foreign Affairs in 1967, Morgenthau wrote that the United States must be more selective in determining when and where it should directly intervene in military conflicts. He ridiculed the notion that America had the resources and the need to directly combat communist aggression everywhere in the world. “Intervene we must where our national interest requires it and where our power gives us a chance to succeed,” he explained. “The choice of these occasions,” he continued, “will be determined not by sweeping ideological commitments nor by blind reliance upon American power but by a careful calculation of the interests involved and the power available.” Something we failed to do in Vietnam.

The journalist Walter Lippmann was a conservative realist when it came to foreign policy. He authored seminal books on American foreign policy, including U.S. Foreign Policy: Shield of the Republic (1943) and The Cold War (1947). Even though President Kennedy and his advisers went out of their way to flatter Lippmann, the administration’s deepening involvement in Vietnam made Lippmann a critic. In 1963, when the president stated that the U.S. may have to bomb and occupy North Vietnam, Lippmann wrote that the “price of a military victory in the Vietnamese war is higher than American vital interests can justify.”

Lyndon Johnson’s escalation of U.S. involvement in the war provoked a stinging rebuke from Lippmann, who wrote that: “A mature great power will make measured and limited use of its power. It will eschew the theory of a global and universal duty which not only commits it to unending wars of intervention but intoxicates its thinking with the illusion that it is a crusader for righteousness, that each war is the war to end all war.” The U.S. needed, Lippmann continued, to get “rid of the globalism which would not only entangle us everywhere but is based on the totally vain notion that if we do not set the world in order, no matter what the price, we cannot live in the world safely.” Lippmann knew first-hand the flaws of Wilsonian ideology, having as a young man been a foreign policy adviser to Woodrow Wilson. For Lippmann, foreign policy was based not on morality but on hard-headed geopolitics. The United States, Lippmann wrote, was not a “global fire department appointed to stop communism everywhere.” And certainly not in Vietnam.

One more conservative realist deserves mention: George F. Kennan, who authored the most famous explanation of the containment doctrine that was later used as justification for our direct military involvement in the Vietnam War. Kennan wrote that explanation in a July 1947 essay in Foreign Affairs under the pseudonym “X.” Walter Lippmann wrote a series of critical columns in response to Kennan’s essay from a conservative realist perspective (he called Kennan’s approach a “strategic monstrosity”). Kennan agreed with the criticism and began to distance himself from the Truman administration’s policies that were arguably consistent with Kennan’s essay. Kennan complained that Truman had “militarized” containment in a way that Kennan had not intended.

Kennan briefly served as Ambassador to Yugoslavia in the Kennedy administration, but as the Johnson administration escalated our involvement in Vietnam, Kennan, who had privately criticized the administration’s approach to Vietnam, went public with a critical piece in the Washington Post in December 1965. There, he noted that a communist victory would result in a ruthless dictatorship in all of Vietnam, but it would not shift the global balance of power against the United States. He later accused the administration of “jumping around . . . like an elephant frightened by a mouse.” He invoked John Quincy Adams’s famous quote about not going abroad in search of monsters to destroy. The United States, Kennan said, needed to liquidate “unsound positions” and withdraw from “extravagant or unpromising objectives.” In a 1967 speech at Harvard, Kennan said that if the U.S. continued to follow its present policy in Vietnam, disaster would result. We needed, instead, to withdraw from Vietnam in a credible manner. 

It took the election of Richard Nixon to the presidency to apply conservative realism to end the Vietnam War. Nixon and his top foreign policy adviser Henry Kissinger understood the limits of American power and the relative unimportance of Vietnam to the global balance of power. Nixon’s policy of Vietnamization was a way to end U.S. direct involvement in the war while seeking to support our longtime ally in South Vietnam. But in the end, Nixon understood that triangulating with Russia and China was more important than saving South Vietnam’s regime, and that even an imperfect “peace” in Vietnam would free the United States to pursue more important global interests.

Unfortunately, succeeding administrations failed to learn the hard lessons of Vietnam and failed to appreciate the wisdom of conservative realists. In the post–Cold War era, the United States abandoned conservative realism by intervening in the Balkans in the 1990s, expanding NATO, and fighting “endless wars” in Iraq and Afghanistan and a global war on terror to spread democracy throughout the world. We promoted the notion of an “Arab Spring” in the Middle East, which only spread terror and chaos. We sponsored a “color revolution” in Ukraine and publicly urged Ukraine’s admission to NATO, which produced the worst aspects of Russian nationalism and imperialism, as George Kennan predicted it would. We have gone abroad in search of monsters to destroy against the sound advice of conservative realists. Fears of World War III have grown.

The second Trump administration appears to recognize these errors and is taking steps to remedy them. It seeks to end the Ukraine War, tamp down the conflict in the Middle East, and deter China from aggression in the Indo-Pacific. Trump is attempting to replicate the triangular diplomacy of Nixon in reverse—improving relations with Russia to shift the global balance of power against China without provoking a war with China. Trump understands that Ukraine, like Vietnam in the 1960s and 70s, is not a vital national interest of the United States, and that pouring more resources into Ukraine will hamper our ability to deter China in the Indo-Pacific. Trump’s conservative realism is reminiscent of Nixon’s, Morgenthau’s, Lippmann’s and Kennan’s. Let’s hope it is not too late.