"European Unity is Under Strain:"

President Obama's recent travels in Europe, which included face-to-face meetings with the leaders of Germany, France, Italy and the United Kingdom, were referred to as a farewell visit by some commentators – but that is far from the truth. Instead, Obama was on a very specific mission to shore up the unity of Europe in the face of a series of challenges that threaten to disintegrate the long sought and hard won community of Europe that has been built in the aftermath of World War II and the collapse of communism.

The very idea of EUROPE, as expressed in the NATO Alliance and the European Union (both now with 28 members), is at risk from multiple threats. These have fed the fears of diverse European peoples and fanned the flames of political movements ranging from populism to opposition to globalization to ultranationalism in both Europe and the United States.

Though the immediate catalyst for these movements that threaten the unity of Europe was the terrorist attacks on Paris and Brussels, the underlying causes are cumulative and of much longer standing. Waves of immigration dramatized by the recent influx of refugees from Africa, the Middle East and Eastern Europe feed xenophobic sentiments in many European states. The slow recovery of European economies and a growing wariness of the impact of foreign trade have limited incomes, been blamed for rising unemployment and forced the imposition of economic austerity regimes. Rising Islamophobia as a response to terror threats fuels calls for more aggressive policing and deepens a spreading sense of public insecurity.

Uncertainty about how to respond to the renewed national assertiveness of Russia and Vladimir Putin, as well as the specific threat posed to Ukraine recalls Cold War tensions and poses potential new border conflicts. Other security issues include the rise of the Islamic State and instability across North Africa and the Gulf region. And all this is happening while the world grapples with the festering conflict in Syria as well as the future of Iran and its place in the regional and global communities.

Even this list is hardly exhaustive, but it serves to dramatize both the complexity of international relations at this moment and the intricate ways foreign policy and domestic politics intertwine. The most immediate concern the European leaders and the American President discussed was "Brexit," the impending British referendum, scheduled for June 23, which will decide whether Britain leaves or remains in the European Union. Also of immediate concern was the surge of refugees into Europe and whether the fragile deal made with the Turkish government to hold refugees in Turkey in order to relieve the pressure on Europe will actually work.

Several strategic concerns were discussed as well. The most immediate was how to expand and improve intelligence sharing among the European states to deal with terrorism more effectively. But, concerns about European states taking on a larger share of common defense costs, about stabilizing Libya and Iraq, and about dealing with the dual problems of the Bashir Assad regime and Russia's role in Syria were also of deep concern. More basic questions dealing with a proposed trade agreement, the Transatlantic Trade and Investment Partnership (TTIP) between Europe and the United States, and cooperation on climate change were also on the agenda of the closed-door mini-summit.

Obama summed up his mission in a final speech delivered in Hannover, Germany, but billed as an "Address to the People of Europe." His words couldn't have been more pointed. "What happens on this continent," the President insisted, "has consequences for people around the globe. If a unified, peaceful, liberal, pluralistic, free-market Europe begins to doubt itself, begins to question the progress that's been made over the last several decades, then we will be empowering those who argue that democracy can't work, that intolerance and tribalism and organizing ourselves along ethnic lines, and authoritarianism and restrictions on the press are the only effective responses to the challenges we face."

"I come to the heart of Europe," Obama concluded, "to say that the United States and the entire world need a strong, prosperous, democratic and united Europe." To sharpen the point, he drove home a critical insistence: the current generation of terrorists "will learn the same lesson as others before them have, which is: your hatred is no match for our nations united in defense of our way of life."