Ten or 20 years ago, the existential question facing the European Union was whether it still had a purpose in a globalized world. The question today is whether the EU can respond effectively to major external shocks.

Europe’s neighborhood is poor and dangerous. South of Gibraltar, income per capita drops more than fivefold. War has recently raged in Ukraine. The Israel-Palestine conflict has continued for more than 50 years. And the war in Iraq barely ended before the mayhem in Syria commenced.

For several decades after World War II, Europe could afford to overlook what went on beyond its borders: Security was the business of the United States. But things have changed. The U.S. retreat from Iraq signaled the limits of its engagement, and the problems in the EU’s immediate neighborhood — not just in Syria, but also to the east and the south — are now knocking on its door. So it would seem that the EU’s top priority should be to protect itself and help stabilize its environment.

Yet three internal fault lines are making it difficult for the EU to achieve these ends. Britain is wondering whether it should exit. Western and Eastern Europe are at odds over the refugee crisis. And France and Germany differ on priorities.

Britain’s torment over EU membership is rooted in history: In 1946, Winston Churchill famously advocated a United States of Europe — but without Britain. Yet there is little substance to British Europhobia: nothing fundamental separates the United Kingdom from the rest of the continent. Tellingly, the British Foreign Office’s rigorous review of how the EU operates did not deliver an agenda for the repatriation of competences.

The only significant demand expressed by Prime Minister David Cameron in his recent letter to the EU concerns internal migration. Britain, the erstwhile champion of labor mobility, has now become wary of foreign workers and wants to limit their access to social benefits. This is a potential sticking point in the U.K.-EU relationship; but it is hardly a reason to end a 4-decade-old partnership.

Polls suggest that Britain’s referendum on continued EU membership, which Cameron has promised to hold by the end of 2017, will be a close call. But it would be both a blunder and a tragedy were Britons to vote for “Brexit” as a form of protection against tumult on the continent.

The second fault line appeared alongside the refugee crisis. By 2014, the EU’s “big bang” enlargement in 2004 could be hailed as a success story, having contributed significantly to swift and peaceful economic and political transition in Central and Eastern Europe. True European unification seemed to be in the making.

Yet the refugee crisis has revealed that the EU’s western and eastern members do not share the same concept of a nation. Most Western European countries have converged, at least de facto, on a nonethnic, nonreligious definition. Most are home to significant ethnic and religious minorities. This has not been an easy transformation, and there are differences in countries’ perceived ability to absorb more immigrants; but the change is irreversible.

Most Central and Eastern European countries, however, object. Hungarian Prime Minister Viktor Orban has developed a fierce anti-Muslim rhetoric. His Slovak counterpart, Robert Fico, announced in July that his country would accept only Christian refugees. Earlier this month, Czech President Milos Zeman addressed a group called the Bloc Against Islam, telling its supporters that they were “not extremists.” And Poland’s new European affairs minister, Konrad Szymanski, did not wait 24 hours after the Paris attacks before using them to denounce Europe’s flaws.

This is not a disagreement over policies. It is a divide over principles — the very principles of the EU’s treaties and Charter of Fundamental Rights. In Germany, especially, any person persecuted on political grounds has a constitutional right to asylum. Contrary to common misperceptions, German Chancellor Angela Merkel acted on the basis of moral values, not demographic self-interest, in letting in about 1 million refugees this year.

Germany rarely expects solidarity from its European partners. At the height of the migrant crisis, it hoped, for once, to receive some. The public, categorical rejection of Germany’s silent plea by countries that continue to benefit massively from European solidarity will not be easily forgotten.

The third fault line lies between France and Germany. Since the Nov. 13 attacks in Paris, security has become the overriding French objective. Meanwhile, Germany is focused on organizing the reception and settlement of a massive influx of refugees.

This divide is more circumstantial than essential. Terrorism may spread to Germany, and refugees may move across borders. Yet, at least for the time being, public concerns and government priorities differ.

Both Merkel and French President Francois Hollande have expressed a commitment to mutual support. France will welcome some refugees, and Germany will dispatch some troops to Mali. But symbolic gestures are not enough. The risk remains that each country feels that it has been left alone at a critical juncture.

More ambitious initiatives have been proposed. Sigmar Gabriel and Emmanuel Macron, the German and French economy ministers, recently called for a common fund to address Europe’s refugee and security challenges and to finance joint policies. The fund would serve as a concrete risk-sharing mechanism and would be a modest, yet meaningful step toward overcoming the deadlock over EU initiatives, if not toward mutualizing defense and security, as some scholars recommend.

Whatever form it takes, greater boldness is clearly needed. Otherwise, the failure to address common risks and challenges may well result in citizens placing exclusive faith in the nation-state, rejecting solidarity, and calling for the permanent restoration of national borders.

It is no accident that the EU’s three fault lines have appeared at the very moment when it is confronted with unprecedented challenges. External pressures reveal internal weaknesses. Europe can either overcome them or succumb to them. The EU’s twin refugee and security crises constitute its moment of truth.

By Jean Pisani-Ferry

Jean Pisani-Ferry is a professor at the Hertie School of Governance in Berlin, and currently serves as the commissioner-general for policy planning for the French government. — Ed.

(Project Syndicate)