As feared, the president of the United States arrived at last week’s NATO summit in a mood of preposterous spleen, profound contempt and shocking rudeness. He insisted on sharing before the cameras imaginary facts that hadn’t a thing to do with the summit agenda, and he refused to listen to anyone who tried, however gently, to correct him. In the words of Robert Kagan, a senior fellow at the Brookings Institution, “These are not negotiating tactics. They are the tactics of someone who does not want a deal.” In a private meeting, Trump reportedly threatened that unless the allies boosted their military spending beyond previous agreements by January, the United States would “go it alone.” Nicholas Burns, a former U.S. ambassador to NATO, implored Americans not to “normalize” this. “He is the first American president since Harry Truman,” Burns noted, “to not believe that NATO is central to American national security interests.” And Burns is a Republican.

Donald Trump’s NATO-bashing surprised no one. He has repeatedly suggested the United States’ postwar security architecture is a “bad deal,” one negotiated by weak and foolish “incompetents.” Foreign policy, in his view, is a zero-sum game; any benefit to another nation must of necessity be a loss for the United States. “NATO countries,” he declared on Twitter, “must pay MORE, the United States must pay LESS. Very Unfair!”

Unfair? A world that revolves around American military, economic and cultural power, and uses the U.S. dollar as its reserve currency?

What Trump fails to understand is that the disparity in spending, with the U.S. paying more than its allies, is not a bug of the system. It is a feature. This is how the great postwar statesmen designed it, and this immensely foresighted strategy has ensured the absence of great power conflict — and nuclear war — for three-quarters of a century.

The open, liberal world order we know today was built in the wake of World War II and expanded after the collapse of the Soviet Union. By design, it is led by the United States; by design, it ensures permanent U.S. military hegemony over Eurasia while uniting Europe under the U.S.’s protection. The goal of this American grand strategy is to prevent any single power from dominating the region and turning on United States and its allies. American hegemony serves, too, to quell previously intractable regional rivalries, preventing further world wars. Dean Acheson, George Marshall and the other great statesmen of their generation pursued this strategy because they had learned, at unimaginable cost, that the eternal American fantasy of forever being free of Europe — isolationism or America-Firstism, in other words — was just that: a fantasy. Four hundred thousand American men lost their lives in the European theaters of the First and Second World Wars. (American fatalities in all of the other 20th century conflicts — including Vietnam, Korea and the Persian Gulf — do not total one quarter of that number.) Our postwar statesmen were neither weak nor incompetent. They were the architects of the greatest foreign policy triumph in U.S. history.

The U.S. military was always an integral part of the plan to unite and rebuild Europe from the rubble.

So successful was this policy that Americans now — most of whom weren’t alive to witness the enormity of these wars — see peace, unity, prosperity and stability as Europe’s natural state. This is an illusion. For centuries, Europe was the fulcrum of global violence. With the age of global exploration, it became the globe’s primary exporter of violence, the tempo and horror of the carnage rising every century with improvements in technology for violence. The Scramble for Africa, the division and colonization of that continent by Europe, is a case in point. The 1884-1885 Berlin West Africa Conference, which assembled the representatives of 13 European powers to settle their colonial claims to Africa by diplomacy in place of arms, did lead to peace in Europe for several years. Africans, however, would not recall these years for their exceptional comity. For example, the Conference indulged King Léopold II’s claim that the Congo Free State was his private property. Ten million Congolese souls perished under his ministrations.

In recognizing this history of blood, however, we must recognize something equally true: In the wake of World War II, liberal democracy saw its fullest realization in the West. This flourishing of peace and human rights cannot be explained by a sudden outbreak of European pacifism. (Consider the 1956 Suez expedition, crushed by an infuriated President Dwight Eisenhower; or the 1954-62 Franco-Algerian War.) It happened because during World War II, Europe destroyed itself, leaving the United States overwhelmingly powerful by comparison, its only rival the Soviet Union. Through the application of economic, diplomatic and military force majeure, the United States suppressed Europe’s internal security competition. This is why postwar Europe ceased to be the world’s leading exporter of violence and became, instead, the world’s leading exporter of luxury sedans.

Only America, and massive power as the U.S. exercised it, could have pacified and unified Europe under its aegis. No other continental country possessed half the world’s GDP. No other country had enough distance from Europe to be trusted, to a large extent, by all parties and indifferent to its regional jealousies. No other country had a strategic, moral and economic vision for Europe that its inhabitants could be persuaded gladly to share.

Indeed, Europeans cooperated with the U.S. program because it created conditions under which both the United States and Europe flourished. The United States assisted Europe’s postwar economic recovery with 13 billion dollars of aid in the form of the Marshall Plan. (In today’s dollars, roughly113 billion.) It midwifed the groupings and treaties that would become the European Union. It brought Europe under the U.S. security umbrella with the NATO treaty. Article V of the treaty, its most important element, declares that an attack on one member of NATO is an attack on all members. These policies were intended not only to counter the Soviet Union, but to condition Europe’s prosperity upon its integration into a single market, with free movement of goods, capital and labor. The founders of these institutions fully intended them to be the foundations of a United States of Europe, much like the United States of America. Profound economic interdependence, they believed, would make further European wars impossible.

At the same time, the United States built an open, global order upon an architecture of specific institutions: the United Nations, the International Monetary Fund and the International Court of Justice. This order is in many respects an empire — a Pax Americana — but it is more humane than any empire that preceded it, with institutions that are intended to benefit all parties. Postwar U.S. statesmen believed that prosperous, liberal democracies that traded freely with each other would neither go to war with each other nor the United States. They ascribed, in other words, to the so-called Democratic Peace theory — a theory with overwhelming empirical support.

The U.S. military was always an integral part of the plan to unite and rebuild Europe from the rubble. Since World War II, U.S troops have been deployed in Eurasia to ensure the continent cannot be dominated by a single power capable of monopolizing its resources and turning them against the U.S. The United States has built overwhelmingly massive military assets there to deter local arms races before they begin, and it has simultaneously assured those under U.S. protection that there is no need to begin local arms races, for their safety is guaranteed. American grand strategy rests upon the credibility of its promise to protect American allies; this credibility rests, in turn, upon U.S. willingness to display its commitment. (The Berlin Airlift, when U.S. troops airlifted supplies to Berlin during a Soviet blockade, was precisely such a display.) In return for the United States’ commitment, U.S. allies have accepted America’s dominant role in the international system.

In the postwar era, just as now, the enemies of liberal democracy sought to undermine the order the U.S. was building. Precisely because the Marshall Plan would strengthen and unite the West under the United States’ protection, the Soviet Union’s propaganda organs cranked into overdrive to denounce it. A cartoon, for example, published in Isvestia in 1949, depicted the Marshall Plan’s administrator, Paul Hoffman, as a fat capitalist bent on destroying the sovereignty of European nations. The French paper L'Humanité, which reliably parroted Moscow’s line, wrote, “After disorganizing the national economies of the countries which are under the American yoke, American leaders now intend conclusively to subjugate the economy of these countries to their own interests.”

The Soviet Union’s criticism of the Marshall Plan and other American involvement in Europe was eerily similar to the language Russia’s now uses in its campaign to undermine NATO and the EU. The vocabulary and tropes of Russian propaganda are widely echoed, wittingly or unwittingly, by far-right, far-left and other antiliberal politicians, parties and movements throughout the West. With the men who built the postwar world order now in their graves, and the memory of carnage and horror buried with them, a very sizeable constituency of Americans has forgotten that their country built this system for a reason—that the United States does not maintain its alliances as an act of foolish largesse. The loudest exponent of the idea that the U.S. is getting rolled, that the European Union was “created to destroy us,” and that multilateral institutions such as the World Trade Organizations assault the “sovereignty” of the nations concerned is, unfortunately, the president of the United States.

It’s hard to understate how foolish and reckless these notions are. History can be shoved down the memory hole, for a time, but reality is never so cooperative. Global free trade sustains modern economic life. An interruption to this trade — carried out chiefly on global shipping lanes safeguarded by the U.S. military — would bring modern life to an end. The Second World War proved not only that isolationism and American-Firstism were fantasies, but exceptionally childish and dangerous ones, at that. In the age of hyper-globalized trade, international air travel, the Internet, nuclear weapons and inter-continental ballistic missiles, these fantasies are even more childish and dangerous. The U.S. may be on another continent, but it is not on another planet.

It is true that the U.S. spends more on its military, in absolute dollars and as a percentage of GDP, than any European country. That was always part of the deal. The U.S. is a global superpower. It can fight a war anywhere in the world, invade any country at will, and (at least in theory) fight multiple simultaneous major wars — even in space. Of course this costs more. It is in America’s advantage to be the only power on the planet that can do this.

Should the unravelling of the order the U.S. built proceed at this pace, the world will soon be neither peaceful nor prosperous.

Conversely, it is not remotely in America’s advantage for other countries to spend as much money on their militaries as we do. Europe is America’s biggest export market, as designed. We want Europeans to spend their money enjoying U.S. goods and services, not razing Flanders to the ground yet again.

Yet Trump’s refusal to deter our shared enemies and protect our allies risks provoking a regional European arms race — exactly what the U.S. has sought to avoid for 74 years. It is an invitation to adventurism from Putin. Trump’s refusal to adopt the encouraging language of past presidents toward European integration, language that until now has been transformed into policy by professional and experienced State Department employees, puts further strain on an already-weakened Europe. Above all, Trump’s overt support for sordid, Kremlin-backed actors who seek to undermine Europe’s unity is unfathomable: How could it be in Europe’s interest, or in ours, for the American president to lend the United States’ prestige and support to Europe’s Nazis, neo-Nazis, doctrinal Marxists, populists, authoritarians, and ethnic supremacists, particularly since all of them are ideologically hostile to the United States?

The damage Trump has deliberately inflicted on Europe’s stability comes at a uniquely dangerous time. Democracy’s so-called third wave — the global blossoming of open political systems after the Cold War — has long since receded. A threat to liberal democracy, in the form of a distinct, rival ideology — illiberal democracy — is ascendant. We see it today in Russia and Turkey — a corrupt, oligarchic, kleptocratic and hollow form of democracy that spreads and consolidates itself through the new technologies of the 21st century.

The global order the U.S. built was based on the principle that only a world of liberal democracies can be peaceful and prosperous. That principle is correct. Should the unravelling of the order the U.S. built proceed at this pace, the world will soon be neither peaceful nor prosperous. Nor will the effects be confined to regions distant from the United States. America will feel them gradually, and then, probably, overnight — in the form of a devastating, sudden shock.

Charles de Gaulle believed the Anglophone world could not, in the long term, be trusted with French security. It led him to withdraw France from NATO’s military integrated command and launch an independent nuclear development program. The independent nuclear program was real, but the withdrawal from NATO wasn’t — a secret agreement kept France in NATO anyway. But, today, with other NATO members obliged to consider the costs and benefits of an independent accommodation with Russia and the risks and rewards of acquiring an independent nuclear deterrent, de Gaulle is saying from the grave, I told you so.

The American-led world order, undergirded by the ideal of liberal democracy, has been highly imperfect. But it has been the closest thing to Utopia our fallen and benighted species has ever seen. Its benefits are not just economic, although those benefits are immense. Its benefits must be measured in wars not fought, lives not squandered.

Yet many Americans have turned their backs history and reality alike. Let us hope pride does not prevent them from realizing this mistake before it’s far too late.

Claire Berlinski lives in Paris. Her forthcoming book, "The New Caesars and the Death of Democracy in the West", is entirely crowdfunded. She would be grateful for your support.