The collective sigh of relief across Europe after the conclusions of the Dutch, French, and German elections earlier this year appears to have been premature. The threat of the far right, as we learned recently, has not been stanched. During this past weekend, the collapse of coalition talks, in Germany, not only imperils Angela Merkel’s continued leadership, but it also adds a terrifying new element of uncertainty to the future of the European Union and the Eurozone. The United Kingdom, which was already struggling to negotiate its exit from the E.U., may be subjected to a painful turning of the screws.

With the election of Donald Trump, the joke has been that Merkel, not the sitting U.S. president, is the leader of the free world—an observation that says more about international opinion toward Trump than it does about Merkel. In the absence of American leadership, Merkel’s forthright commitment to globalism, statecraft, free trade, and human rights have made her a bulwark of the liberal order against a rising tide of far-right populism. But Merkel’s recent rejection of identitarian politics and her open-door policy toward refugees, amid a spate of terrorist attacks in France and Belgium, have also made her a target of the social forces she has struggled to contain. On Sunday night, Germany’s chancellor, the most skilled and resilient European politician of her generation, failed to create the “Jamaican” coalition—so called because the combination of the party colors of Merkel’s C.D.U., the sister party C.S.U., the Greens, and pro-business Free Democrat Party (F.D.P.) makes up the Jamaican national flag—when the leader the F.D.P. pulled out because of what he called a “lack of trust.” A towering pillar of the E.U. and, indeed, of the entire European project, is suddenly tottering.

Frank-Walter Steinmeier, the German President, subsequently asked the parties to think again about coalition. They weren’t in the mood for further talks, however, and Merkel was left with the option of forming a minority government. She is a woman used to the exercise of power and, by the end of the day, she concluded that another election would be better for her and the country. There may be an element of bluff in this. It is unlikely that she will persuade her former partners in the S.P.D. to form another grand coalition; the party, after all, feels that its association with Merkel in the previous administration caused it to lose votes. But the F.D.P. might not want another roll of the dice.

To Americans, this must look like an utterly forgettable storm in a European teacup. But the crisis—the worst in Germany for decades—underlines two hard realities in Europe. First, migration is still a very live issue for all Europeans, and particularly for Germans, who under Merkel’s government have absorbed well over one million migrants into their society since 2015. Second, without German economic and political stability, Europe is unlikely to address the great issues that must be tackled if the rise of right-wing nationalist parties is to be halted.

Challenges from the essentially fascist parties of Geert Wilders and Marine Le Pen were defeated in the Dutch and French elections, but the AfD (Alternative for Germany) did astonishingly well in Germany. It claimed 94 seats in the Bundestag, which rendered it the third most represented party in the country. Another election would certainly favor an insurgent party that has made much of attacking Merkel’s record on migration and draws support from the authoritarian lands of the formerly Communist Eastern Germany.

This, incidentally, is an important development of the last few years in Europe, and it is not limited to the former G.D.R. Across Eastern Europe, particularly in Poland and Hungary, far right, anti-immigrant governments have challenged the social and democratic foundations of the great postwar project of the E.U. Poland’s right-wing Law and Justice party has made grave inroads on the independence of the judiciary and free speech and, in Hungary, legislation has undermined the legal system, media freedom, and human-rights protections. Without a solid social-democratic government in Germany, these tendencies, which are essentially nationalist and Eurosceptic, are bound to increase. If the center does not hold, things may fall apart.

The world is much changed in the hundred years since Europe was convulsed by a clash of empires. Today’s fractures are nothing like the formation of confrontational alliances that led to the Great War. But recent events certainly suggest that the world order is less stable than the post-Cold War era suggested. We have not reached the end of history yet. A lot may happen in the run-up to Christmas. However, if Merkel is forced into another election as leader of the conservative party, one theory is that the German people will see the minority parties as a luxury they cannot afford and back her. Yet these days, as Brexit has demonstrated, it is dangerous to assume that Europeans will vote for stability and a secure economic future.

In the meantime, this uncertainty has had a crucial impact on European economic confidence. Tilmann Galler, a JPMorgan market strategist and respected commentator on the subject, voiced concerns at the beginning of the year about the prospect of the Dutch, French, and German elections. Now he is again worried. “The collapse of the coalition talks in Germany on Sunday night brought back the topic of political uncertainty to financial markets,” he told the Financial Times. “Merkel’s position seems to be significantly weakened. This could leave Europe’s largest economy politically paralyzed for the time being, reducing the chances for any breakthrough in the E.U. reform agenda or the Brexit negotiations.”

In France, the Napoleonic new president, Emmanuel Macron, has been pushing the European reform agenda on the Euro currency, youth unemployment, migration, the common defense force, and further integration of markets and corporate rules, but he cannot do this without a strong partnership with Germany, particularly as he has his own enormous challenge of modernizing France’s employment laws and has lost a lot of support since his spectacular victory in May.

All this does not bode well for little Britain, which postures on the margins of Europe claiming an unearthly exceptionalism in the Brexit negotiations. If Merkel, the one person in Europe who can save the U.K. from its chosen path of self-destruction, is distracted by the political crisis at home, a sensible solution to the Brexit problem seems far less likely. That will damage Europe as well as the U.K., which could be hit with a catastrophic economic downturn and capital flight.

Merkel stands for reason and stability in a troubled and exceptionally unpredictable world. One day Europe must do without her, but we have to hope that day will not arrive anytime soon. If she fights and does not gain the necessary majority—the exact same position that her British counterpart Theresa May find herself in—we enter uncharted waters.