Campaign posters for Carsten Sieling of the center-left Social Democrats (SPD) and Carsten Meyer-Heder of the center-right Christian Democrats Union (CDU) compete in Bremen. (Fabian Bimmer/Reuters)

— If there was ever a safe haven for Europe’s center-left, it was the brawny industrial hub of Bremen.

Thick with workers at the region’s bountiful factories and pulsating harbor, the city-state voted for the Social Democrats — Germany’s oldest party, famed for its Nazi-era resistance — for more than 70 years. But perhaps not this one. 

In elections to be held Sunday, the party that effortlessly dominated is in danger of losing its grip. It’s a once-unthinkable indignity that reflects a broader identity crisis for parties across the West — including America’s Democrats — that present themselves as champions of workers, unions and social democracy, but have seen support wither in their former heartlands.

For Germany’s Social Democrats, the outlook is especially dire.

“What we’re witnessing is a really big moment,” said Andreas Klee, director of the politics program at Bremen University. “It’s the burial of a party.”

The party is not ready to declare its demise. Even as the Social Democrats careen toward a new nadir — with dismal results expected not only in Bremen but throughout the country in European parliamentary elections — party leaders and activists are plotting a revival.

And as with Democrats in the United States — as well as like-minded parties throughout Europe — much of the momentum is coming from the left. 

Just as Rep. Alexandria Ocasio-Cortez (D-N.Y.) has ignited passions among liberal American voters, the leader of the Social Democrats’ youth wing, the Adidas-wearing Kevin Kühnert, is leading an insurgency within his party aimed at a bolder, more radical course. 

He vigorously defends socialism, and he recently dominated German political conversations for days with his suggestion that automaker BMW be collectivized. “Without collectivization,” he told the German newspaper Die Zeit, “overcoming capitalism is inconceivable.”

Kevin Kühnert, head of the youth wing of the German Social Democrats (SPD), visits a Berlin apartment building where residents are concerned about affordable housing. (Carsten Koall/Getty Images)

The comments provoked a furor — including stinging condemnations, many from within the Social Democrats’ ranks — but also emboldened supporters who feel the party’s coziness with the ruling conservatives has led it to an electoral dead end. 

Even without going as far as Kühnert would like, leaders of the Social Democrats (SPD) have signaled they are prepared to turn left. The party recently disavowed welfare cuts implemented during the SPD’s last run atop the federal government, an era when the party saw capturing the center as the surest path to power. 

Meanwhile, some SPD leaders are mulling whether to break off their long-running role as junior partner in a coalition government with Chancellor Angela Merkel’s center-right Christian Democratic Union. That decision would probably come with the choice to draw a more vivid distinction between Germany’s two traditionally dominant parties.

The left has been invigorated elsewhere in Europe as the center-left declines. In Greece, a radical leftist party won two elections and has driven the old center-left party to the brink of extinction. In Britain, the Labour Party is led by Jeremy Corbyn, a figure once relegated to the far-left fringe. And in Spanish elections last month, the center-left Socialists came out on top with an unapologetic defense of progressive policies, including a 22-percent minimum wage hike.

“Among social democrats across Europe right now, it’s mainstream to look left,” said Joachim Schuster, a member of the European Parliament and longtime Bremen politician. “We’ve had years of cooperation with the conservatives, and most of us are not too happy about it. We need to establish our differences.”

The overall picture for both the center-left and center-right in Europe is one of decline. In this month’s elections for the European Parliament, both factions are on pace for big losses, with each camp likely to shed about 20 percent of its seats as the continent’s politics continue to fragment.

But the struggles of social democratic parties have been more existential. The situation in Bremen shows why. 

Britain’s opposition Labour Party leader, Jeremy Corbyn, attends the launch of his party’s European election campaign in Chatham, England, on May 9. (Daniel Leal-Olivas/AFP/Getty Images)

For decades, elections here were a foregone conclusion, with powerful unions helping to ensure their members made their way from the factory floor to the voting booth to cast ballots for the SPD. But the workers of old are gone — and so are the party’s voters.

“Twenty years ago, you took a tour of the Airbus factory here and you saw people with tools actually making the planes. Now, you walk in and it looks like a dentist’s office. People are working on laptops. It’s very sterile,” said Klee, the politics professor. “The core problem with the SPD is they don’t have a voter base anymore.” 

That reality has brought the party to the brink of an astonishing result: In state elections here Sunday, which coincide with the European vote, polls show the SPD may lose to the CDU for the first time in Germany’s post-World War II history.

Defeat could have national implications, making it more likely that the SPD would pull out of the coalition with Merkel’s party and force new federal elections.

Although that is considered unlikely until the end of the year, it’s the outcome that Kühnert and his allies are pushing for — a necessary prerequisite, he argues, for the party’s revival after years in which it has governed with Merkel while sinking in the polls.

“We were always against the grand coalition with the conservatives,” said Sebastian Schmugler, who leads the SPD’s youth wing in Bremen. “Now we can say, ‘We told you so.’ ”

Schmugler, a 24-year-old law student, said the party needs to compromise less and fight for its ideals more or it risks trending toward irrelevance.

“The young generation can’t understand it. We have our positions, but then we make a deal and we lose too much,” he said. “So we’re just going down, down, down.”

But ditching the coalition might not be enough to reverse the party’s fortunes.

The depth of the problem was on display at a recent debate at a Bremen vocational school. At one time, the SPD would have been the clear crowd favorite. But this time, the room appeared divided among a number of mainstream parties.

Kevin Kühnert, speaking in Wittenberg, Germany, says his party should abandon its centrist partnership and move left. (Jens Schlueter/Getty Images)

And the questions from the students — hundreds of whom listened intently for 90 minutes as the candidates spelled out positions — were hardly in the SPD’s wheelhouse. None focused on wages, pensions or social welfare. Instead, the students asked about artificial intelligence, immigration and, most of all, climate change.

Especially on the latter two issues, the SPD has struggled to form clear positions as it has sought to balance competing interests among supporters whose positions don’t fit neatly with any ideology. Other parties have not had the same problem — and have benefited as the SPD has bled.

“We have leaks in both directions,” said Björn Tschöpe, leader of the SPD in the state parliament. “To the Greens because of climate change and on identity issues to the far right.”

Tschöpe, a gray-haired party veteran, cautioned that any lurch to the left will come with costs. And he asserted that Kühnert, while asking the right questions, is “wrong” to think that collectivization of private companies is the answer.

The party’s rebuilding, he acknowledged, would need to be a long-term process, with even strongholds like Bremen potentially lost along the way.

“If you govern a place for over 70 years, you are responsible for its good points and its bad,” he said. “You can’t blame anyone else.”