French Socialist President François Hollande knew which way the winds were blowing. His announcement last week that he would not seek reelection was a response to record-breaking unpopularity. But it also reflects weaknesses haunting the left and center-left throughout the democratic world.

Donald Trump’s victory may thus be only a particularly alarming portent for moderate progressives who, less than two decades ago, were confidently on the march.

Now, the radicalization of the right threatens the consensual welfare-state capitalism that gave the West decades of relative social peace and prosperity. France is the latest example, and a dramatic one.

If there is one taken-for-granted assumption in French political life, it is that Marine Le Pen, the candidate of the far-right National Front, will find her way into the runoff in next year’s presidential election. The first round will be held in April; the second, between the top two finishers, in May.

François Hollande announced that he would not seek reelection in 2017. He is the most unpopular president in the history of modern France, with an approval rating dropping as low as 4 percent. (James McAuley, Jason Aldag / The Washington Post)

But the surprise, at least to much of the media and political class, was the victory of François Fillon in the November primaries for the country’s main center-right party, the Republicans. Fillon, a traditionalist Catholic, is a critic of multiculturalism and what he sees as Muslim encroachment on French identity. He routed former president Nicolas Sarkozy and the favorite, former prime minister Alain Juppé.

Juppé was the moderate in the group, and a significant number of Socialist Party supporters crossed into the other side’s contest to help him. They hoped that if the country eventually faced a center-right vs. far-right choice in the general election runoff — that’s the betting line now — the former would be at least acceptable to them. But after Sarkozy was eliminated, Fillon defeated Juppé in a landslide.

This parlous choice gave the already done-for Hollande an excellent reason to announce that he would not seek reelection. “As a Socialist, because that’s my life’s commitment, I cannot accept, I cannot resign myself, to a scattering of the left, to its breaking up,” Hollande declared Thursday night. “Because that would take away all hope of winning against conservatism, and even worse, against extremism.”

Well, yes, but the French left is already in pieces. It faces not only divisions but also subdivisions within its divisions.

Emmanuel Macron, 38, quit Hollande’s cabinet to form a new centrist political movement built around modernizing French politics and embracing economic openness. He is in a long line of politicians — going back to the center-left heyday of Bill Clinton and Tony Blair — who have positioned themselves against both the traditional left and right. “I want to unite the French, I’m not reaching out to the left or the right, I’m reaching out to the French,” he said in a television interview.

Polls suggest that Macron may be able to appeal to some of the same anti-system feeling that is motivating votes for the far right. Still, his Third Way politics are more in keeping with the prosperous and optimistic 1990s than with our gloomier and more nationalistic moment.

And with Hollande out of the race, Macron could find himself challenged for votes from the moderate left by another political modernizer from inside the Socialist Party, Prime Minister Manuel Valls.

The splintering on the progressive side goes further still. Outside the Socialist Party, Jean-Luc Mélenchon is running as the champion of the harder left. Arnaud Montebourg, the former economics minister, comes from the Socialist Party’s own left wing, pushing for protectionism to battle “the excesses of globalization.”

Hollande’s withdrawal creates a sense of at least remote possibility among socialists, and the European left and center took heart at the result of Sunday’s presidential election in Austria, where Norbert Hofer, the candidate of the far right, was defeated by Alexander Van der Bellen, a former Green Party leader. Hollande called the outcome “a choice for Europe and for openness.”

The French Socialist primary in January will likely feature Valls, Montebourg and possibly others. But its winner could still hemorrhage votes to Macron in the center and Mélenchon on the left.

Every country has its particularities. Hollande’s problems were personal as well as ideological: Even his own political base came to see him as hapless and indecisive. But the center-left’s troubles and the hardening of opinion on the right reflect the rise of a politics of fear across so many of the democracies, including the United States.

Its elements include fear of the impact of globalization on the living standards of the working class, fear of immigration and the dilution of national identity, and fear of terrorism.

A center-left that once thrived on a politics of hope must either come to terms with these fears or actively push back against them. It is divided because it cannot decide which strategy is more promising — and which is more in keeping with its values.

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