AUSTIN, Texas — In the midst of U.S. exhortations that European nations increase their defense budgets to meet their NATO obligations, one observer wrote an article for an U.S. audience trying to explain why Europeans, mired in an economic recession, resisted these pressures. The prospect of such defense spending, he said, “threatens living standards to a greater degree than Americans can realize. The issue of guns or butter is a real one.” Facing such difficult trade-offs, it was no wonder that Europeans would resent such hectoring.

The year was 1951 and the observer was Reinhold Niebuhr — the theologian, social ethicist, journalist, political activist, professor, and preacher who was one of the mid-century’s most prominent U.S. public intellectuals. Largely forgotten for a time except in academic circles, Niebuhr has enjoyed something of a public rebirth in recent years, with President Barack Obama identifying him as his “favorite philosopher.”

Niebuhr pioneered the development of the “Christian Realism” school of thought, which emphasized balancing power with moral restraint in an imperfect world. “Order precedes justice in the strategy of government, but…only an order that implicates justice can achieve a stable peace,” he wrote in a pithy summary. Niebuhr’s anti-utopianism made him a fierce critic of totalitarianism, whether of the fascist or communist variety, and a dedicated albeit measured defender of democracy as the political system most consonant with human nature. Among his many other influences, Niebuhr did much to shape domestic support for the United States’ intervention in World War II and its subsequent Cold War posture.

His transatlantic commitments led him to form a set of ideas about how and why the Atlantic Community — as he termed it — existed. Seeking to understand differences in attitudes, Niebuhr identified several causes of European anti-Americanism, including the economic contrast between European social democracy and less-fettered U.S. capitalism, the resentments inspired by U.S. power, and the purported crassness and shallowness of a technology-obsessed U.S. culture. His work serves as a reminder not only that tensions between Europe and the United States are an age-old story, but so are many of the specific causes of those tensions. However, Niebuhr also matters for transatlantic relations today for much more substantial reasons: as the United States and Europe are buffeted today by new challenges and an uncertain future, he offers some insights that may help in restoring the transatlantic community to a firmer foundation. Niebuhr grounded his Atlanticism on three principles that still resonate today: shared values, shared interests, and shared obligations.

In Niebuhr’s words, the Atlantic Community did not have “a unified culture” but rather shared “a way of making diversity tolerable under conditions of freedom.” It is “composed of nations who have discovered the way to community despite diversity,” a unifying and binding principle in its own right that forms the foundation of the Community’s strength and resilience.

Niebuhr’s intellectual core also rested on a strong sense of realism — in his mind, the Atlantic Community’s core was also based on shared interests. In 1952 he wrote that “the ‘Atlantic community’ is becoming a reality…partly because the exigencies of history are forcing mutual tasks upon it.” These “mutual tasks” in the charged context of the early Cold War included the shared interests of “the necessity of a common defense against tyranny” and “mutual economic measures” to promote prosperity. Today’s circumstances may be different, but transatlantic interests are not. The ongoing travails of the U.S. and European economies demonstrate our shared economic interests. In the security realm, not only is war unimaginable among the nations of the Atlantic Community, but going to war without each other’s assistance is almost equally inconceivable.

And because Niebuhr believed in the union of interests and values, he easily embraced the Atlantic Community’s shared obligations to the wider world. He described NATO as having a “double purpose” of protecting the values of the Atlantic Community and contributing “this possession to the whole enterprise of integrating a global community of nations.” “Atlantic values” were not merely Atlantic but were ultimately universal, he believed, and offered a rich inheritance to the world.

Appreciating Niebuhr today helps guard us against imagining an idyllic era in transatlantic relations that in reality never was. We should not panic over “Mars and Venus,” but find a way of navigating transatlantic differences while appreciating underlying commonalities. Niebuhr also reminds us of the value of having religious leaders add another dimension to transatlantic relations. And his worldview demonstrates that values and realism can and should be incorporated within each other. In this era of material scarcity, and of ideological challenges posed by militant Islamism and authoritarian capitalism, the Atlantic Community would do well to recapture a Niebuhrian appreciation of its interests and confidence in its ideals.

William Inboden is a Distinguished Scholar at the Strauss Center for International Security and Law, Assistant Professor at the University of Texas-Austin, and a non-resident fellow with the German Marshall Fund of the United States (GMF). This article is adapted from a longer paper, “Diversity under Freedom: Reinhold Niebuhr and the Transatlantic Community,” published this week by GMF.