This article was originally posted at Providence.

In November 2013, tens of thousands of Ukrainians filled the central square of Kiev to protest President Viktor Yanukovych’s decision to reject an “association agreement” with the European Union. Waving European Union flags, the crowds chanted slogans demanding to be part of the West. As Liudmyla Babych, a saleswoman from Kiev, told The Guardian: “We want to be in Europe.”

There are good reasons to want to be part of the European community. Like no other multi-ethnic region of the world, the Europeans can boast strong commercial ties, free-market economies, a system of international law over the use of force, and a shared commitment to liberal democratic values. A war among the European states is nearly unimaginable, an achievement of great importance to the United States.

Nevertheless, two years after the Ukrainian revolution that eventually ousted its thuggish president, enthusiasm for the European project has reached a new low—even among Europeans.

There are of course the ongoing economic woes: the Greek debt debacle remains unresolved, and most European economies are struggling with high unemployment and low growth rates relative to the United States. The gross domestic product of the 19 countries sharing the euro currency is smaller now than it was before the 2008 economic meltdown.

There is the rise of the Islamic State and terrorist violence that has exposed the vulnerability of Europe’s unprecedented achievement: its open internal borders among its 28-member states. Twice in less than a year, terrorist cells—moving freely across Europe—struck Paris with devastating results. “France is at war,” declared Socialist President François Hollande. The French government is trying to amend the constitution to allow the president to suspend civil liberties without parliamentary approval. Open borders mean a unique openness to Islamist terror.

There is the Syrian civil war, which has created a refugee crisis that has sent shock waves throughout European capitals. From January to October of this year, over 1.2 million migrants entered the European Union illegally. The influx of these individuals, mostly Muslim, is stoking xenophobia, as we well as legitimate worries about the compatibility of Islam with liberal democracy. Although Germany’s Angela Merkel had pledged to open the country to asylum-seekers, a public backlash elicited a promise to “reduce the number of refugees appreciably” before Germany was “overwhelmed in the long run.” Countries such as Hungary and Austria have built fences to keep them out, and most EU states have tightened their border controls.

And, of course, there is Ukraine, which has suffered the Russian takeover of its Crimean Peninsula and remains engaged in a fierce battle with Russian-backed separatists in its eastern region. Although EU states have imposed sanctions on Moscow, they have done nothing to hinder Russian designs in Ukraine. Meanwhile, some European leaders appear eager to cooperate with Vladimir Putin to help resolve the Syrian conflict.

All of these challenges have exposed the fundamental weakness of the entire European project—namely, its inability to muster the political leadership required for effective action. This vulnerability was hinted at in a lengthy essay by Jim Yardley in The New York Times. “Every elected national leader knows there is no political mileage to try to lead on European issues or push for more integration,” Frederick Erixon, director of the European Center for International Political Economy, told the Times. “The European idea is now a rapidly declining trend.”

The fact is that the European Union—with its generous welfare schemes, rejection of nationalist impulses, marginal military expenditures, and pacifist foreign policy—could only work in a world without crises. In other words, it could never succeed in the world as we actually find it. “It might never have been realistic to envision a United States of Europe,” concedes Mr. Yardley. Not realistic at all, in fact—and yet the reasons for its failures still elude liberal elites, especially those in the United States who want America to become more like Europe.

Whether from historical amnesia or ideological blindness, Mr. Yardley appears not to grasp that Europe owes much of its political and economic success to the United States. He notes that the European Union has built a stable and diverse economy, supported by democratic ideals. He explains that Europe prides itself on being a Western superpower “without the bellicosity or laissez-faire hardheartedness of the United States.” Yet Mr. Yardley fails to mention that few of Europe’s achievements would have been possible without American leadership: its moral seriousness, economic dynamism, the success of its democratic institutions, and the projection of its military power.

Robert Kagan, author and senior fellow at the Brookings Institution, has correctly observed that the United States created—and has sustained—the architecture for international security that made the European project conceivable. “Europe’s rejection of power politics and its devaluing of military force as a tool of international relations have depended on the presence of American military forces on European soil,” writes Kagan in Of Paradise and Power: America and Europe in the New World Order. “American power made it possible for Europeans to believe that power was no longer important.”

Yet the banality of this conceit has been exposed as never before—in Ukraine, Syria, Iraq, in Paris, and in the ongoing struggle against the fascist barbarism of the Islamic State. A European Union that fails to confront these new realities will be of little help to the United States—or to the liberal democratic order that it claims to represent.

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.