Since the Second World War, American presidents have repeatedly gone before the United Nations General Assembly and made a similar argument: The United States has national interests just like any other country, but in the modern era those interests are increasingly international in scope and shared by people around the world, requiring more of the multilateral cooperation that the UN was founded to foster.

John F. Kennedy argued that nuclear weapons necessitated “one world and one human race, with one common destiny” guarded by one “world security system,” since “absolute sovereignty no longer assures us of absolute security.” Richard Nixon spoke of a “world interest” in reducing economic inequality, protecting the environment, and upholding international law, declaring that the “profoundest national interest of our time” is the “preservation of peace” through international structures like the UN. In rejecting tribalism and the walling-off of nations, Barack Obama asserted that “giving up some freedom of action—not giving up our ability to protect ourselves or pursue our core interests, but binding ourselves to international rules over the long term—enhances our security.” These presidents practiced what they preached to varying degrees, and there’s long been a debate in the United States about the extent to which America’s sovereign powers should be ceded to international organizations, but in broad strokes the case for global engagement was consistent.

On Tuesday, during this year’s UN General Assembly, Emmanuel Macron, the French president, made this case. But the American president didn’t. Instead, Donald Trump inverted the argument: Contemporary challenges, he told the world leaders assembled in New York, are best tackled by self-interested states that work together when and where their interests overlap. “If we are to embrace the opportunities of the future and overcome the present dangers together, there can be no substitute for strong, sovereign, and independent nations—nations that are rooted in their histories and invested in their destinies,” Trump said.

Macron, by contrast, emphasized interdependence rather than independence. The lesson from humanity’s collective history in recent decades is that, from Mali to Saint Martin, “we are inextricably linked to each other in a community of destiny” and  “planetary responsibility,” the French president noted in a speech soon after Trump’s. “There is nothing more effective than multilateralism in our current world because all our challenges are multilateral: war, terrorism, climate change, the digital economy.”

Trump and Macron even diverged in their interpretation of the postwar period. World War II was won because “patriotism led the Poles to die to save Poland, the French to fight for a free France, and the Brits to stand strong for Britain,” Trump recounted, and the UN “was based on the vision that diverse nations could cooperate to protect their sovereignty, preserve their security, and promote their prosperity.”

Macron, meanwhile, began his address by stating that he wouldn’t be standing before the UN as the leader of the French Republic had people from America and Africa, to Asia and Oceania, not resisted “the barbaric regime that had seized my country,” recognizing that “their freedom and their values depended upon the freedom of other women and of other men who lived thousands of kilometers away from them.” He and his country also owed a “debt” to those who later created the “international order”—including the UN, the rule of law, and mechanisms to facilitate exchanges between peoples—to restore the “values of tolerance, of freedom, of humanity” that the Second World War “had flouted” and that held the worst instincts of humankind “at bay.”

Trump vowed to put America’s interests first, and suggested other leaders do the same. In condemning the authoritarian leaders of Cuba and Venezuela, he proclaimed that “nations of the world must take a greater role in promoting secure and prosperous societies in their own regions.” Macron rejected parochialism. Peace, freedom, and justice are not solely to “be enjoyed in our own corner,” he contended. “If we don’t stand up for those values, then all of us will be affected.”

Macron preferred to describe the world’s problems on an international scale. He expressed concern about the “dictatorial trends” on display in countries like Venezuela and the “jihadist terrorism” afflicting all continents, warned that North Korea threatened efforts to stop the proliferation of nuclear weapons, and praised the Paris climate-change agreement as a pact between states and generations. Trump acknowledged that international problems such as terrorism and drug-trafficking demand international solutions. But he nevertheless dwelled on the level of the nation-state, which he characterized as “the best vehicle for elevating the human condition.” He called out the suffering that the socialist dictator of Venezuela had inflicted on his own people and gave notice that the “rocket man” in North Korea, in brandishing nuclear weapons at the United States and allied nations, was embarking on “a suicide mission.”

Trump again and again stressed America’s power and capacity to prevail against its enemies, echoing the argument of two of his top advisers earlier this year that the world isn’t a “global community” but “an arena where nations, nongovernmental actors and businesses engage and compete for advantage.” He claimed that the U.S. economy and military were stronger than ever and—in the most stunning moment of his speech—threatened to “totally destroy” North Korea, a fellow UN member state. Macron lamented that “we have allowed the idea to proliferate that multilateralism is … the tool of the weak,” that “we were stronger if we took unilateral action.” If the world continues down this path, if the history that birthed the UN is forgotten, “it’s the survival of the fittest that will prevail,” Macron cautioned.

These stark differences in worldview help explain why Macron, and other like-minded Western European leaders, are currently at odds with the Trump administration on the top global issues of the day, including the North Korean nuclear crisis (Macron favors a multilateral diplomatic solution, Trump prefers economic pressure and threats of force); the Iran nuclear deal (Macron wants to preserve it, Trump wants to tear it up); and the Paris climate deal (Macron is committed to it, Trump pulled out of it).  

But they also testify to divisions that endanger the United Nations itself. If the world’s major powers can’t agree on what the UN is for, what does that mean for the future of the organization? Kevin Rudd, a former Australian prime minister who has studied ways to reform the UN, likes to point out that while we may take the United Nations for granted, order in international relations is the exception, not the rule. “Since the rise of the modern nation-state,” he has observed, “disorder has been the dominant characteristic of inter-state relations.” As I wrote last year, after interviewing Rudd:

Over the last 500 years, Rudd notes, “there have been four major efforts in Europe to construct order after periods of sustained carnage”: in 1648, after the Thirty Years’ and Eighty Years’ wars; in 1815, after the French Revolutionary and Napoleonic wars; in 1919, after World War I; and in 1945, after World War II. “The first three of these ‘orders’ have had, at best, patchy records of success. The jury is still out on the fourth.”

This week, Trump alluded to the fragility of the United Nations: “The true question for the United Nations today, for people all over the world who hope for better lives for themselves and their children, is a basic one: Are we still patriots? Do we love our nations enough to protect their sovereignty and to take ownership of their futures? Do we revere them enough to defend their interests, preserve their cultures, and ensure a peaceful world for their citizens?” What is urgently needed, Trump said, is “a great reawakening of nations.”

Macron made the same point by posing the polar opposite question. “I cannot say whether my successor … in 70 years’ time will have the privilege of speaking before you,” he reflected. “Will multilateralism survive this time of doubt and change?”