BRUSSELS >> The European Union has long had to deal with the challenge of being led by a dominant Germany. But suddenly it finds itself facing a different realization — the only thing worse than a strong Germany may be a weak one.

Germany is hardly collapsing, but the failure of Chancellor Angela Merkel to form a coalition government presents a profound crisis of leadership for Europe and a protracted period of uncertainty, at a time when it can least afford it.

Serious decisions on the eurozone, migration, asylum, defense and other issues — let alone negotiating Britain’s exit from the bloc — were already put off until after the French and German elections this year.

Now they will be further delayed, waiting for plodding Germany to work through this new political quandary.

The looming sense of paralysis is a credit to the stature Merkel has gained in 12 years as chancellor. She defined Europe’s response to the euro debt crisis. Along the way, she has borne criticism for German overweening. But she has also earned respect for her ability to forge compromise.

She has been central in forcing through stiff sanctions on Russia over Ukraine, winning praise in Europe for standing up to both President Donald Trump and President Vladimir V. Putin of Russia.

In short, Merkel has been the indispensable leader in Europe. Any weakening of her political position at home, or domestic preoccupation, is a serious blow to a bloc still struggling to salvage its future.

The pain will perhaps be felt most keenly by the ambitious French president, Emmanuel Macron, who has laid out a striking agenda of European reform. Macron’s plans always depended on German support.

Macron has audacity, but he is too new and viewed too skeptically by other leaders, including those from Central Europe, to actually “lead Europe,” if Europe can in fact be led.

“Even if weakened inside, Merkel had great authority outside of Germany, and a style that lent itself well to coalition building,” said Mark Leonard, the director of the European Council on Foreign Relations. “She has the ability to bring other countries together for essential action. And Macron can’t do it on his own.”

With Merkel weakened and Germany facing the possibility of a caretaker government before new elections in the spring, European Union reform will be put through another extended delay.

For now, German politics are a kind of poker game, with the main actors using the threat of new elections as a way to see whether a working coalition can yet be formed.

As ever, the straws that broke the back of the German coalition talks were largely about domestic politics, including taxes and migration, noted Jackson Janes, the president of the American Institute for Contemporary German Studies.

“But the implication of an uncertain German political future makes serious foreign policy ripples, particularly in Europe,” Janes said. “France has been waiting for the Germans to get closure on their own political leadership in order to pursue a stronger Franco-German partnership.”

“The lingering uncertainty surrounding Brexit requires a strong German presence in those negotiations,” he added. “There are continuing challenges facing Europe as it tries to pursue a deepening of its security policies.”

Equally important, key European countries — the Netherlands, France, Germany — narrowly skirted the onslaught of populist forces in elections this year. Italy and now Germany, again, may face a repeat test early next year.

Macron has been blunt that the bloc has a limited time to get things right, or face a worse outcome the next time elections come around.

“It’s pretty bad for Macron,” Leonard said. “He has this window of a year before the European elections while he’s still powerful to try to get things done.”

Macron has hung his political fate, and that of Europe, on hopes for a strong Franco-German engine to drive reforms. That prospect looks more in doubt under almost any scenario.

“Either Merkel survives in a weaker position and is less able to deliver, or she goes, and that will be a big crisis for his agenda, because Europe is so fragmented and she had the ability to build consensus,” Leonard said.

At the EU’s summit meeting of leaders next month, Macron hoped for a groundbreaking deal on the outlines of reform of the monetary union.

It was never clear that Merkel would go along with all or any of these proposals for a deeper fiscal and political union, especially if she were in a new coalition with the Free Democrats. But it will be some time now before Germany is ready even to debate them.

“Germany is still pretty stable and a caretaker government can make decisions,” said Christoph von Marschall of Der Tagesspiegel, a daily. “But what we were waiting for — a new dynamic because Macron would finally have a partner to revitalize the European locomotive or the Franco-German couple — this is postponed and that is serious.”

Josef Janning, the head of the Berlin office of the European Council on Foreign Relations, said that “Macron risks losing the momentum of his presidency.”

His controversial domestic reforms were justified at home because they would supposedly produce confidence in Germany and more dynamism in Europe. “But this narrative is falling apart because Berlin is not answering,” Janning said.

Devout supporters of the British exit from the EU — known as Brexit — saw Merkel’s troubles as helping their cause — “the political weakness of the strongest EU state makes our negotiating position stronger,” said Jacob Rees-Mogg, a Conservative member of Parliament.

But the European consensus on the Brexit negotiations remains unchanged, and it is more likely that Britain would suffer from a weakened Merkel, less able to argue to her European colleagues that everyone benefits from concessions for a good relationship with London.

“I don’t think it makes much difference to Brexit in the short term, because the positions of various parties in Berlin are all pretty hard-line on the issues,” said Charles Grant, the director of the Center for European Reform.

“But it might matter in the long term, because if the negotiations get stuck, Merkel and Macron could intervene to get a deal,” he said. “That might not happen if Merkel disappears, because the EU got used to her knocking heads together.”

Germany’s dominance in Europe would continue, Grant said. “But the credibility she built up over 12 years, as someone respected by everyone, that might disappear.”

Merkel has also been the European leader, given her lengthy experience, who has dealt most visibly with neighbors like Putin and President Recep Tayyip Erdogan of Turkey. That will not change, Janning said, but it would be harder for her to argue for continued sanctions inside Europe against the Hungarians or Italians. As a caretaker leader, she would be unable to make any new commitments to limit migration from North Africa, for instance.

Europe is dealing with the political effects of the economic and migration crisis and the loss of faith in traditional technocratic elites and consensus politics.

Various “anti” parties have filled the vacuum, from the far left to the far right, building on anxieties about national identity, globalization, migration, Islam and jobs, taking votes from the larger parties and making majority coalitions much harder to build in more diverse parliaments.

Germany is only the latest European country to feel this wave of change. But Merkel’s re-election had been considered all but foretold.

Instead, her fate is unclear. And while it is unclear, Europe must continue to twiddle its many thumbs.

As von Marschall said, “What has been postponed already for almost too long is now postponed even longer.”

© 2017 The New York Times Company