Germany towers over Europe, and Europe looks to Germany for leadership. But Germany is a cautious leader, looking to other countries for support. And with Chancellor Angela Merkel stepping down soon, its future role in Europe is uncertain.

Since the unification of West and East Germany in 1990, Germany has grown to be Europe’s most influential country. Its economy is Europe’s largest. Its population is the largest in Western Europe.

Germany has provided Europe with diplomatic, political, economic and security leadership. No other European nation is in a position to step up, with the United Kingdom divided over Brexit and France preoccupied with economic problems and unrest.

German leadership is at the center of discussions of European politics. Europeans are always asking what Germany wants and what role it will play.

But Germany has been careful about exerting leadership. It does not seek to dominate Europe.  Perhaps because of the shadow of two World Wars, or from Merkel’s innate sense of caution, German leaders hesitate to act alone. They want partners. They want to lead but seek consensus.

This poses a challenge for how other countries in Europe deal with Germany’s strength. Will they share the burdens, commit their own resources and play a larger role in addressing Europe’s problems? The future of European leadership becomes a delicate balance between Germany and the other European countries, and Europe’s ability to provide stability and prosperity for its people is at stake.

The rise of Germany has gone hand in hand with the ascent of Merkel, Germany’s chancellor since 2005. She has been Europe’s acknowledged leader and a force for stability. A pragmatic centrist, she has steered Germany on a moderate path and kept it at the center of European politics and decisions.

But she stepped down last year as head of her political party, the Christian Democratic Union, and announced she would leave office soon. Her successor as party leader, Annegret Kramp-Karrenbauer, may or may not be in line to become chancellor. Leadership will be up for grabs at a time when Europe faces serious problems, including slowing economic growth, immigration and refugees, the rise of far-right parties, challenges to the rule of law and Russian interference in Ukraine. And at a time when authoritarian and populist governments have come to power in Italy and countries of the former Soviet Bloc.

Germany isn’t immune from these problems. The anti-immigrant Alternative for Germany party is now the third-largest group in the Bundestag. Whether Germany can maintain social cohesion, integrate refugees and address income inequality and other economic challenges – as it transforms its leadership – is in doubt.

This uncertainty also comes as NATO, which is marking the 70th anniversary of its founding, needs to spend more on equipment and modernization to maintain military readiness. Yet Germany has fallen short of a commitment to raise defense spending to 2% of its gross domestic product, raising questions about its reliability and leadership in military and security affairs.

For the United States, Europe is our most important military ally and our largest trading partner in Europe. While President Donald Trump has downplayed the transatlantic partnership, we have an enormous stake in seeing that Europe prospers and remains stable. There is every reason for Europe to remain at the center of U.S. foreign policy.

But Europe is at a crossroads, and Merkel’s upcoming departure will leave a blank space in its leadership. The question looms: Can Germany maintain its own stability – and its ability to lead Europe – not only during its next leadership transition but beyond?

By Lee H. Hamilton