In Sunday's European Parliament elections, the Alternative for Germany (AfD) won 11% of the vote in Germany — almost 2 percentage points less than the right-wing populists scored in federal elections in 2017.
Although the party finished in fourth place nationally, it fared far better in Germany's formerly communist eastern states.
In Saxony and Brandenburg, the AfD beat Chancellor Angela Merkel's Christian Democrats (CDU) into second place. In Thuringia, it was only 2 points behind.
Worryingly for Merkel, all three states go to the polls once more in regional elections in autumn.
Despite huge investments since German reunification in 1990, former East German states still suffer from higher unemployment, lower living standards and lower wages than the rest of the country.
The AfD tapped into voter frustration by branding mass migration to Germany and the nation's transition to renewable energies as clear economic threats in a region where coal is king and the vast majority of citizens are ethnically German.
"Eastern Germans are wired differently, first and foremost because the classic social setup of the [former] West is nonexistent in the [former] East," Alexander Gauland, co-leader of the AfD, told reporters on Monday.
The party's hand had been strengthened, he said, in "freedom-loving" parts of the country.
Gauland noted that the result showed a "divided Germany." Indeed, the party's anti-immigration stance did not resonate in western regions.
Young and urban voters plumped for the climate-friendly promises of the Greens, who secured 20.5% of the vote. That meant that the Greens finished in second place behind the CDU in a nationwide vote for the first time in their history, overtaking the Social Democrats (SPD), the junior partners in Merkel's coalition government.
"This was a vote for protecting the climate," Greens MEP Sven Giegold said.
Climate change is shaping up to be the main battleground as Gauland declared the Greens to be his party's "main enemy."
"The Greens will destroy this country and our job must and will be to fight them," he said.
While the Greens won the hearts and minds of young voters in the west, the AfD has positioned itself as an "advocate of the eastern German population," Alexander Häusler, a sociologist at the University of Applied Sciences in Dusseldorf, who researches right-wing extremism and populism, told DW.
With the prospect of the first AfD state premier being elected in the autumn now firmly on the cards, Germany's political establishment is reflecting on how to best reposition itself in the former East to stem the rising populist tide.
"It won't be a quick and easy task for us as the CDU if we find ourselves in the center [of political issues]," Annegret Kramp-Karrenbauer, leader of the CDU, told reporters on Monday, referring to the party's struggles in eastern Germany.
That's especially the case given the lack of faith in both the CDU and the SPD to advocate for positions that resonate, Florian Hartleb, a political scientist researching European populist and right-wing movements, told DW. Just one in four voters believe that the governing parties have the best answers to questions about Germany's future, according to a recent survey by the pollster Infratest dimap.
As such, the results of Sunday's European elections are a precursor to a political future divided between the AfD in the east, and the Greens in the west — with Germany's traditional political parties struggling for relevance, said Häusler.
"The Greens and the AfD are waging a cultural battle," he said. "On the one hand, there are those who support an open, pluralistic, minority-protecting, cosmopolitan society. And on the right, a defensive, protective stance."