As Europe seeks to absorb a massive wave of newcomers, the challenges are becoming strikingly apparent. First, with no advance planning, European countries have had to move quickly to address the immediate issues of shelter and other urgent needs, all the more so as winter arrives and options like tents for housing become unfeasible. The task is formidable. More than one million new arrivals have come to Germany, the preferred destination, in 2015 alone. Each individual, as I know from my own experience working with refugees from behind the Iron Curtain, is a world unto his or her own, often with medical or psychological issues, concerns for family members left behind, anxiety about the uncertainty of what lies ahead, and a ton of questions about a new and totally unfamiliar country. Second, EU member states, especially in Central Europe, are at loggerheads over the migration issue. Several countries - some openly, others quietly - blame Germany's Chancellor Angela Merkel for triggering the wave of newcomers by her unexpected message of welcome in September, spurred by a humanitarian impulse to help people clearly in need. Indeed, The Times (of London) referred to "Merkel's Migrants" in a page-one headline. Meanwhile, within her own political party, the CDU, and its Bavarian sister party, the CSU, debates surrounding her action have been robust. Notwithstanding calls for EU unity and solidarity in "burden sharing," the feuding persists. In AJC's recent meetings in Berlin and Brussels, it emerged that of the 160,000 migrants to be allocated by the EU Commission to various other member states, under a proposed plan of mandatory quotas, only a tiny handful have actually gone to their new homes so far. The resistance to resettlement by some, though not all, EU nations has been fierce. They insist that they were not consulted in the original decision and, in any case, already have enough social and economic difficulties without adding to the list. Third, the security dimension of the migration wave cannot be ignored. The migrants were not part of an orderly process that began in third countries where they filled out applications for refugee status, were screened by officials, and then, if approved, sent to a country prepared to receive them. Rather, the process has been quite chaotic. Overwhelmingly male and young, the migrants have reached Europe's shores in unprecedented numbers, often after harrowing journeys, with identity papers that may or, in some cases, may not be authentic, or with none at all. How can receiving countries establish in each and every case who they are and verify their stories? For instance, according to reports, a certain percentage who claim to be Syrian are not, but declare themselves to be because an informal pipeline, using social media, has conveyed that Syrians have the best chance for filing successful asylum applications in Europe. Moreover, there are fears that ISIS and other groups are infiltrating terrorists into the human wave, perhaps even providing them with stolen or counterfeit IDs. These fears have been intensified by the November 13th attacks in Paris that killed 130 people. Two of the perpetrators reportedly arrived in Europe via the migration wave through Greece. Further, there is concern that if disillusion should set in among some newcomers - because, say, reality does not match expectations - jihadist cells will try to lure them as foreign fighters or local operatives. As it is, many European security agencies are quite overwhelmed by the current challenges of tracking thousands of suspects, especially those who have traveled to Iraq and Syria and returned, and their recruiters. Generally speaking, there is inadequate staff for 24/7 monitoring and surveillance; insufficient information-sharing among EU member states; years-long, inconclusive debates between advocates of privacy rights and data protection versus more intrusive security measures; outside, at times tolerated, funding (by Saudi Arabia, for instance) of Salafist and other extremist religious activity; and limited intelligence cooperation from Turkey, the preferred route for Europe's foreign fighters heading to and from Iraq and Syria. Adding new dimensions to Europe's security agenda will prove an enormous burden for stretched agencies. Fourth, acculturation of the newcomers looms large. Until now, many EU member states have had difficulties in integrating waves of migrants from the Middle East and North Africa. Going forward, they will have to do better. While there have been many remarkable success stories of integration, there have also been notable failures. Examples abound. Molenbeek in Belgium, Malmö in Sweden, and several "banlieues" (suburbs) of Paris illustrate the phenomenon of marginalized, forlorn communities that too often have resulted in parallel societies; cycles of high student dropout rates, unemployment, and violence; and the blossoming of extremist religious groups. Apropos, it's noteworthy that a number of foreign fighters are second-generation, born in France, Belgium, the U.K., etc. In addition, the new migrants come from overwhelmingly non-democratic societies - Syria, Iraq, Afghanistan, Yemen, Eritrea, etc. They often have had little experience with norms of Western countries, including gender equality, faith as a private choice, separation of religion and state, and pluralism and mutual respect, and may or may not find the transition easy to embrace. In a meeting with Yazidi refugees in Germany last week, an AJC delegation heard not only horrific accounts of the persecution they endured in Iraq, but also of difficulties experienced in Europe at the hands of other migrants who brought with them their prejudices against this oft-targeted, non-Muslim community. And Europe's Jews may wonder whether anti-Semitism in the countries of origin will also transfer with the migration, adding to rising levels of Judeophobia. Finally, the migration appears to have no end in sight, given the hope of millions more to escape endemic war, poverty, and despair in the Middle East and Africa, not to mention the desire of those who have already made it to Europe to reunite with family members left behind. In turn, this has created a troubling backlash, most recently in France, fueling populist movements that assail the political establishment and the concentrated power of the EU, question Europe's ability and will to control its own borders, and advocate nationalist, at times stridently nativist, platforms. Thus, Europe, which has achieved such an extraordinary degree of postwar peace and cooperation, is now buffeted by large-scale migration; growing security concerns; internal feuding; invigorated extreme right-wing movements; and questions about the EU's capacity to respond effectively to issues that may well define the character and cohesion of European nations in the years ahead. In other words, the stakes could not be higher. Whether the EU and its 28 member states will pass the test of their most severe crisis to date remains to be seen. As a long-time transatlanticist and Europhile, I fervently pray they will, as they must. -- This feed and its contents are the property of The Huffington Post, and use is subject to our terms. It may be used for personal consumption, but may not be distributed on a website.