It has been 80 years since World War II ended. That historic moment brought celebration, euphoria, and collective relief. The devastating war was finally over; fascism, it seemed, had been defeated. The mood in the United States was perhaps best captured by the iconic photograph of a U.S. Navy sailor kissing a woman in New York City’s Times Square on Aug. 14, 1945, after the news broke that Japan had surrendered.
But it didn’t take long for Americans to realize that international threats were far from over. In the aftermath of World War II, the Cold War between the Soviet Union and the United States quickly took hold. With the advent of atomic and nuclear weapons, the stakes of avoiding a full-scale confrontation increased dramatically.
In response, Presidents Harry S Truman (a Democrat) and Dwight D. Eisenhower (a Republican) promoted a vision of liberal internationalism. Working with Congress, they built a series of institutions and policies that have endured into 2025. This postwar order helped prevent the worst military conflict humankind has imagined and established a degree of stability in Europe that proved essential to America’s national security and economic strength.
Today, that entire post-WWII system is under serious threat. President Donald Trump has launched a systematic attack on what Truman and Eisenhower created. As with so many elements of American politics, Trump has exposed the fragility of long-standing assumptions. Once subjected to a frontal assault by the president of the United States, foundational pillars of foreign policy began to crumble.
Trump has severely strained or ruptured key international relationships in just a few months, even managing to provoke antagonism from Canada. Elon Musk took a chainsaw to the U.S. Agency for International Development. Trump has continually delivered sharp criticism about NATO and raised concerns over how committed he remains to the alliance while also offering words of praise to autocratic countries such as Russia and Hungary. He humiliated Ukrainian President Volodymyr Zelensky on television and made clear that U.S. support for his country in its war against Russia has a fast-approaching expiration date.
The president has hollowed out much of the national security apparatus established in the late 1940s. When Henry Kissinger served as national security advisor and secretary of state under Presidents Richard Nixon and Gerald Ford in 1973 and 1975, it was understood that one person wielded immense influence in the halls of government. When earlier this month Marco Rubio became only the second individual to hold both roles, most observers rationally assumed his function would be to rubber-stamp whatever the president desired.
Even before World War II had ended, President Franklin D. Roosevelt warned that America’s obligations to the world would continue. In his final inaugural address in January 1945, Roosevelt said: “[W]e have learned lessons—at a fearful cost—and we shall profit by them. We have learned that we cannot live alone, at peace; that our own well-being is dependent on the well-being of other nations far away. We have learned that we must live as men, not as ostriches, nor as dogs in the manger. We have learned to be citizens of the world, members of the human community. We have learned the simple truth, as Emerson said, that ‘The only way to have a friend is to be one.’ We can gain no lasting peace if we approach it with suspicion and mistrust or with fear.”
Despite all the challenges and setbacks this vision has faced since 1945, many observers assumed its basic premise endured. Neo-isolationism was presumed dead, and liberal internationalism was the default. Even after Trump’s first term, the infrastructure seemed to have survived.
Yet as Trump uses his second term to dismantle the international system that has guided U.S. foreign policy for decades, the foundation’s weakness has become starkly apparent.
From a historical perspective, the risks were always there. In the early years of building the national security state, liberal internationalists who argued for permanent global engagement faced fierce resistance. During congressional debates over the National Security Act of 1947—which created the Department of Defense, the National Security Council, and the Central Intelligence Agency—proponents had to overcome concerns that a “garrison state” would foster the very kind of totalitarianism America claimed to oppose.
Historian Michael Hogan’s A Cross of Iron detailed the depth of that resistance: from old-guard Republicans like Ohio Sen. Robert Taft, who opposed Truman’s commitments; to progressives like Vice President Henry Wallace, who feared needless escalation with the Soviets; to university scientists worried about the constraints of federally funded research. Between 1945 and 1953, Truman sought a middle path—limiting new institutions and embedding safeguards, such as placing a civilian secretary of defense in charge of the military. Congress mandated a 10-year minimum before a former general or admiral could be eligible for appointment without a congressional waiver.
Truman also accepted budget cuts to domestic programs to satisfy concerns from fiscal conservatives that permanent wartime footing would blow up the budget. Truman settled on the peacetime Selective Service System to raise troops in time of war instead of the more ambitious universal military training (UMT) program he wanted, which would have required all men to undergo military training when they reached 18. A wide-ranging coalition of opponents, spanning from the Socialist Labor Party of America to the National Education Association, had attacked UMT as antithetical to the founding vision of the nation.
Fears about the North Atlantic Treaty Organization (NATO) have also been long-standing. In the middle of the Senate debate over the treaty, Taft declared: “It is with great regret that I have come to the conclusion that I cannot vote in favor of ratifying the North Atlantic Treaty because I think it carries with it an obligation to assist in arming at our expense the nations of western Europe, because with that obligation I believe it will promote war in the world rather than peace.”
Even Eisenhower, a military leader who helped establish NATO, privately expressed frustration with European allies, believing they needed to shoulder more responsibility. Criticism of NATO only grew stronger after the Cold War ended in the early 1990s. As the Soviet threat receded, more voices questioned the rationale for binding U.S. foreign policy to other nations’ interests.
Others feared that expanding NATO would unnecessarily provoke Russia. In 1997, the Arms Control Association warned then-President Bill Clinton that “the current U.S.-led effort to expand NATO, the focus of the recent Helsinki and Paris Summits, is a policy error of historic proportions. We believe that NATO expansion will decrease allied security and unsettle European stability.”
The United Nations, too, has long been in the crosshairs. In 1964, Sen. Barry Goldwater, the Republican presidential nominee, dismissed the U.N. as ineffective. The John Birch Society spent the 1960s campaigning for U.S. withdrawal. In 1984, President Ronald Reagan pulled the U.S. out of UNESCO, accusing the body of corruption and anti-Western bias. At the Reform Party convention in 2000, Pat Buchanan called for U.N. eviction from U.S. soil, saying: “Mr. Kofi, I want to be polite, but if you are not gone by year’s end, we will send a few thousand U.S. Marines to help you pack,” referring to then-U.N. Secretary-General Kofi Annan.
Skepticism toward liberal internationalism has never been confined to the right. As Johnson escalated the Vietnam War, many liberals and progressives turned against the foreign-policy consensus. The war discredited the “best and the brightest,” in David Halberstam’s phrase, and undermined confidence that American leaders were truly acting in the name of democracy rather than empire. Student activists and their allies on Capitol Hill railed against what Eisenhower had called the “military-industrial complex” in his farewell address—an unholy alliance of contractors, lawmakers, and defense officials producing bloated budgets and strategic drift.
The end of the draft in 1973 passed with little protest. And when Sen. Frank Church’s committee revealed in 1975-76 the CIA’s and FBI’s secret operations—including domestic surveillance and unauthorized assassinations—public trust cratered. As the final report concluded: “Intelligence agencies have undermined the constitutional rights of citizens, primarily because checks and balances designed by the framers of the Constitution to assure accountability have not been applied.”
Although agency leaders worked to restore trust, it remained fragile. In the post-9/11 era, revelations about surveillance and torture further eroded public confidence. “Americans did this to an Iraqi prisoner,” said CBS’s Dan Rather in a somber voice as 60 Minutes 2 in 2004 showed the image of a prisoner wearing a black cape and hood, forced to stand on a small cardboard box with his fingers connected to a machine. The prisoner was told, Rather said, that if he fell off the small box he would be electrocuted. “Some days we’re not always proud of our soldiers,” admitted Mark Kimmitt, deputy director for coalition operations in Iraq. The anger intensified when it became clear that the revelations from the Abu Ghraib detention facility were not anomalies but part of the government’s strategy.
Like Republican presidents, Democrats have likewise attacked U.S. allies for not doing enough. Then-President Barack Obama, a staunch internationalist, told the Atlantic’s Jeffrey Goldberg in 2016 that “free riders aggravate me.”
The hard truth is that the postwar international order never rested on solid political ground. Resistance has existed from the start. Preserving what Truman and Eisenhower built has always required ongoing effort. Sometimes, critiques targeted the system’s core principles; other times, they stemmed from disastrous policies or institutional abuse. Either way, when Trump targeted this pillar of American governance, it began collapsing more quickly than many foreign-policy veterans had anticipated.
Even with a clear-eyed understanding of liberal internationalism’s shortcomings, its contributions are undeniable. The alliances, institutions, and commitments that emerged after World War II helped prevent nuclear catastrophe, stabilize global affairs, underpin American economic strength, and provide experienced counsel during moments of national crisis.
Supporters of the post-WWII system now face a monumental fight. The opposition is not only vocal—it is deeply rooted. Unless they can defend their vision and respond candidly to legitimate criticisms, they may soon witness the collapse of the world order they spent a lifetime defending, replaced by the abyss of America First.
The post The Post-World War II System Was Always Fragile appeared first on Foreign Policy.
