This article was originally posted at The Weekly Standard.

Ventotene, Italy

On this ragged and remote island in the Tyrrhenian Sea, when Europe was in the throes of the Second World War, a political prisoner dreamed of a continent unified and at peace.

Altiero Spinelli, who had joined the Italian Communist party as a young man in the 1920s, was arrested for his activities opposing Mussolini’s fascist regime and sentenced to 16 years in prison. He was not idle. Writing on cigarette papers, Spinelli and a fellow inmate, Ernesto Rossi, produced a political treatise now considered the birth certificate of the European Union. Their “Ventotene Manifesto,” smuggled out of prison in the summer of 1941, called for a European federation of democratic states, a political union designed to permanently tame aggressive nationalism.

“A free and united Europe is the necessary premise to the strengthening of modern civilization, which has been temporarily halted by the totalitarian era,” they wrote. “The question which must be resolved first, failing which progress is no more than mere appearance, is the definitive abolition of the division of Europe into national, sovereign States.”

The manifesto was widely circulated and soon a new social-political movement, the Movimento Federalista Europeo, was born. As leader of the MFE after the war, Spinelli played a decisive role in furthering European integration—as a writer, activist, and member of the European parliament. Always the radical in the room, Spinelli enjoyed a career that is a case study in political idealism rising from the ashes of war.

In the years after the First World War, the watchword was disillusionment. Italian society was in tatters. About 578,000 soldiers were dead, over 10 percent of those mobilized. Returning soldiers encountered a staggering degree of poverty, one of the highest inflation rates in Europe, and stark class differences. Although Italy had fought with the victorious Allies, the government failed to win territorial concessions at the Versailles peace conference. Critics assailed “the ruling class,” which “humiliated and betrayed our soldiers” and “finally wasted and utterly destroyed our victory.”

Benito Mussolini and his “Black-shirts” swept into Rome in October 1922, promising to restore Italy’s ancient greatness and declaring the end of Europe’s experiment in liberal democracy. “For the Fascist, everything is in the State,” he proclaimed, “and nothing human or spiritual exists, much less has value, outside the State.” Two years later, Spinelli joined the Communist movement to thwart this nationalist and totalitarian vision.

Many Italians, of course, voted with their feet: Hundreds of thousands, including my grandparents, arrived in the United States between the wars. My maternal grandfather, Giuseppe Aiello—coincidentally a native son of Ventotene—arrived in Brooklyn just months before Mussolini’s rise to power. Michele Loconte, a veteran of the Great War, brought his family to New York City in the 1930s—and never looked back. For many Italians, the future seemed bound up with America’s democratic example of prosperity, opportunity, and political freedom.

Though a lifelong Communist, Spinelli admired the American system with its checks and balances and “infinite productive resources.” While among the ranks of the confinati—the antifascists imprisoned under Mussolini—he reportedly studied the federalist debates over the American Constitution. He would become a tireless advocate for “a United States of Europe.”

The 1957 Treaty of Rome, creating the European Economic Community (EEC), was a major step in that direction. But Spinelli was unsatisfied: An adviser to federalist leaders such as Alcide De Gasperi, Paul-Henri Spaak, and Jean Monnet, he pushed hard for the creation of a parliamentary assembly, a European constitution, and a common economic policy. Nearly every proposal for European integration bore his fingerprints.

Two years before his death in 1986, Spinelli helped to write the treaty establishing a federal European Union, dubbed “the Spinelli plan,” adopted overwhelmingly in the European parliament. Though member states rejected the agreement, it gained new life in the 1990s, inspiring the 1992 Maastricht Treaty, which created a European economic and monetary union.

Seventy-five years later, Spinelli’s belief that America’s political union could be replicated across Europe—at the expense of national sovereignty—is crumbling. The institutions he helped to create, centered in Brussels, are struggling to cope with a debt crisis, moribund economic growth, and rising resentments over immigration. Britain’s decision to leave the European Union may signal the beginning of a general unraveling.

Earlier this year, Italian president Matteo Renzi warned that “Europe is in danger of collapsing.” Last month, in a symbolic effort to “relaunch” the European project, Germany’s Angela Merkel and France’s François Hollande joined Renzi in Ventotene to pay homage at Spinelli’s gravesite. Europe can enjoy a future of “unity and cohesion,” Hollande said, but only if its leaders combat “dislocation, egotism, folding in on ourselves.”

Living through the Second World War, many like Spinelli viewed nationalism as Europe’s greatest enemy. “Men are no longer considered free citizens who can use the State in order to reach collective purposes,” he complained bitterly in 1941. “They are, instead, servants of the State, which decides their goals.” His idea of Europe as a tightly integrated political and economic community—a monolithic super-state—was intended as the remedy.

But Spinelli’s political vision—grounded in Marxist materialism—failed to reckon with the deep attachments intrinsic to human societies: a shared sense of history, culture, language, and religion. Faith in a borderless, supranational Europe was destined to collide with the realities of the human condition.

Herein lies the paradox: For his entire political career, Spinelli denounced the impulse to regard the nation-state as “a divine entity.” Yet to a growing number of Europeans, the administrators of the European project—aloof, autocratic, and lacking accountability—have demanded a similar obeisance. Perhaps it’s time to look for more modest, earth-bound alternatives.

Joseph Loconte is an associate professor of history at the King’s College in New York City and the author of A Hobbit, a Wardrobe, and a Great War: How J.R.R. Tolkien and C.S. Lewis Rediscovered Faith, Friendship, and Heroism in the Cataclysm of 1914-1918.