Martin Schulz, chairman of Germany’s Social Democratic Party, faces an uphill battle in his bid to defeat Chancellor Angela Merkel in September’s elections. (Odd Andersen/AFP/Getty Images)

There is a German word, “Wechselstimmung,” that means a mood for political change. 

Americans felt it. So did Britons. The French, too. Whether it takes hold here will decide whether Martin Schulz, Germany’s Social Democratic candidate for chancellor, has an opportunity to unseat Angela Merkel, 62, who is seeking her fourth term in a September election. 

Schulz, 61, will make his case Sunday at the Social Democrats’ convention in Dortmund as he seeks to reboot his campaign after the center-left party took a drubbing in state elections this spring. But analysts say it may already be too late. A surge in the polls surrounding Schulz’s selection as party chairman in March has evaporated, and the Social Democrats (SPD) now trail Merkel’s center-right Christian Democratic Union (CDU) by double digits. 

Bucking the trend elsewhere in the West, German voters may opt to stay the course. 

“The polls are not the way they should be,” said Ralf Stegner, deputy chairman of the SPD. He acknowledged that the party has struggled to distinguish itself from Merkel’s bloc, with which it has governed in a grand coalition since 2013. When voters see little distance between the two leading parties, he said, the far-right Alternative for Germany — which appears poised to enter the federal Parliament for the first time — is able to position itself as the only distinct option.

“Therefore, I’m not for a centrist course,” Stegner said.

The SPD’s dilemma, heightened by its working relationship with the conservatives, reflects a predicament facing other left-leaning parties caught between centrist impulses and their base. And in a moment of electoral volatility, there is no clear solution. Emmanuel Macron, a former Socialist finance minister, charted a path to the French presidency from the middle. But Jeremy Corbyn, in leading Britain’s Labour Party to a strong result in general elections this month, and Bernie Sanders, in mounting a spirited bid for the U.S. Democratic presidential nomination last year, showed how a more leftist message can resonate. 

Schulz spent the past week touting plans to safeguard pensions and tax the rich, issues that are expected to form the centerpiece of the platform ratified in Dortmund. A draft released last month promised major new investment in infrastructure and education, as well as a security crackdown.

In a speech Thursday in the capital calling for more public housing, Schulz warned that social neglect drives voters to the extreme. 

“I know because of my own background that Germany doesn’t only consist of central Berlin,” he said. “I can tell you what it was like for us as kids when my parents, small civil servants in North Rhine-Westphalia, finally had their own rooms for the boys and the girls thanks to state funding.”

Schulz has distanced himself from labor-market reforms introduced under the last SPD-headed government but has otherwise not made clear how his vision of “social justice” differs substantially from past initiatives, or even from the plans of other parties, said Gero Neugebauer, a political scientist at the Free University in Berlin. 

The party’s mistake, said Gesine Schwan, a two-time SPD nominee for president, is assuming that Merkel is unassailable.  

“Schulz is afraid to attack Merkel. He has overestimated himself during the hype, thinking he could make the election about personality,” Schwan said, referring to the period after Schulz’s rise to the party leadership, when polls pointed to a virtually neck-and-neck race. “Of course, on personality Merkel is very strong. The point is that she has a very bad policy, and this is where he has to attack her — her changes on taxes, no clear vision for Europe or climate policy, and the security issue, which doesn’t have to be a conservative point.”

Malu Dreyer, SPD governor of the southwestern state of Rhineland-Palatinate, noted that Schulz still has several months to campaign. She said surveys suggest that many voters remain undecided.

“He understands and recognizes injustices in our society and can bring this across in a very authentic way,” Dreyer said. 

A former bookshop owner and mayor who fought his way back from alcoholism, Schulz often uses his personal story to highlight his message of social solidarity. He served as president of the European Parliament for the past five years, stepping down in January. Neither an outsider nor a central player in national politics, he faces a steep climb in opposing Merkel, who has been in power for 12 years. 

Unlike in countries where mainstream politicians have faltered, the chancellor has overseen a period of relative prosperity in Germany. Last year, the country’s economy expanded at a faster clip than at any point over the past half-decade, with employment and wages both on the rise. Meanwhile, Merkel has achieved star power as an exponent of liberal values, expected to counter Donald Trump, keep Vladimir Putin in line and take a hard line with Britain over its exit from the European Union. 

Her global preeminence is a source of satisfaction even for those outside her party. It also blunts Schulz’s pro-Europe message, as well as his attempt to campaign as a bulwark against the far right.

“The uncertain environment on the international stage is playing to her favor, because she is the one who is in charge, she is the one who has experience in office,” said Peter Matuschek, head of political and social research at the Forsa Institute, a leading German polling company. 

Matuschek said the SPD could resurrect itself on Sunday. But, he said, “it might come a little bit too late.”