Right-wing populists are expected to make strong gains in the German state of Thuringia on Sunday, in further proof of Alternative für Deutschland’s growing strength. However, outrage sparked by Nazi slogans, death threats and the recent deadly attack on a synagogue may have dampened expectations of the party seizing control from the embattled left.

In what has been billed as a fight for the political heart of Germany, the anti-immigration, anti-establishment AfD, which made strong gains in the states of Saxony and Brandenburg last month, was expected to take around 23%, according to final polling, more than double its previous result of 10.6% in the east-central state.

Demonstrators hold up a banner reading ‘Who votes for Höcke votes for fascism’ referring to AfD candidate Björn Höcke. Photograph: Christof Stache/AFP via Getty Images

It is vying for second place with the Christian Democrats (CDU) of Angela Merkel, which was on on 22.9% in final polls.

Die Linke, which under its popular leader, Bodo Ramelow, has led Thuringia in a coalition with the Social Democrats and the Greens since 2014, is widely expected to win with around 30%, but is likely to struggle to form a majority government.

The AfD framed its campaign from the start as a cultural clash with the established parties. It has accused those in power of failing to deliver on the promises made since the fall of the Berlin Wall 30 years ago to citizens of the former communist east, including 2 million Thuringians.

Bodo Ramelow is the current governor of Thuringia. Photograph: Jens Schlueter/Getty Images

“We have been left behind,” said Astrid, a care worker from Mühlhausen, using a phrase that has come to define supporters of the AfD in recent elections: “abgehängt”, literally “hung up” or “abandoned”.

The 59-year-old, who did not want to give her surname, said she had voted for Die Linke at the last poll but was now considering supporting the AfD.

Johannes Brüns, the mayor of Mühlhausen, said the city of 36,000 had much to be proud of: Johann Sebastian Bach was once the resident organist, it boasts one of Germany’s largest medieval centres and is the birthplace of John A Roebling, the civil engineer behind New York’s Brooklyn Bridge.

“It has a lot going for it,” Brüns said. “But the people here have had a tough time having to reorientate themselves. Nineteen out of 20 eastern Germans had to find new jobs after the fall of the Berlin Wall. Some left and succeeded, some stayed and succeeded, but some got left behind and the insecurities have remained. There is a considerable amount of frustration.”

The AfD’s Björn Höcke is a former history teacher. Photograph: Michael Dalder/Reuters

The town prospered over centuries thanks to its expansive textile industry. But much of that was closed by the Treuhand, the agency tasked with restructuring and selling state-owned businesses in the German Democratic Republic (GDR) before unification in October 1990. Often that involved buying up the competition, making use of the know-how before liquidating the companies.

“Resentment about that sits deep to this day,” Brüns said. Resentment which, he added, was only reinforced by issues such as pensions being lower than those in the west and more recently, the refugee crisis.

“The most frequent comment I hear from the 50-plus is: ‘There’s little recognition for what we’ve achieved in our lives, but the government doesn’t hold back when it comes to helping refugees.’”

The AfD’s success – polls repeatedly show it has the support of around a quarter of voters in Thuringia – was the direct consequence of such neglect, he believed.

The AfD has gained much support from people who felt they were left behind by East Germany’s transition from communism after the fall of the Berlin Wall. Photograph: Michael Dalder/Reuters

Torben Braga, an AfD candidate, made no bones about the fact his party was busy tapping into that emotion with its election slogan, “Vollende die Wende” (Complete the transition), a reference to the switch from communism to liberal democracy, which is widely interpreted as an invitation by the party to overturn the status quo, just as protesters who brought down the East German regime did.

“This is an election and elections are all about speaking to people’s emotions,” said Braga. “Thirty years after the peaceful revolution of 1989, there are still serious differences between east and west, including the level of wages, the infrastructure, and employment figures. There are still no Dax-registered companies from eastern Germany; there is huge emigration from east to west. This bothers people a great deal and the AfD has managed to effectively instrumentalise these emotions for its own gain.”

Steffen Thormann, 25, a political science student and a candidate for Die Linke in his native Mühlhausen, said he had grown up surrounded by people harbouring such frustrations. “The Berlin Wall still exists in many people’s heads, even those of my age who weren’t born when it fell,” he said. “Lots of people are disappointed that, for them, life didn’t improve after reunification in the way they had hoped. The AfD has been very successful at fuelling the envy, but Die Linke has constantly tried to win people’s trust with its solid social policy, including putting more money into schools and kindergartens.”

The AfD’s election slogan: ‘Complete the transition’. Photograph: Andreas Gebert/Reuters

Astrid, who was walking her dog on the main square waiting for an AfD election rally to start, said she had been “an excited 29-year-old” when the wall came down.

“When the factory I worked in was closed down, I retrained as a care worker,” she said. “I got to know west Germans, I was open to everything.” Now, she said, she struggled to pay her rent, and worried how she would make ends meet on her pension.

The arrival of hundreds of refugees in Mühlhausen in 2015 had felt like a further threat to her existence, she said. “Those in power cut the numbers of police and said they didn’t have the funds to fix the holes in the road, but suddenly money was found to house the newcomers.”

Astrid was waiting to hear Björn Höcke, the AfD’s leading candidate and head of its extremist wing who many say is radicalising the party.

CDU candidate Mike Möhring has refused to enter into a coalition with the AfD. Photograph: Jens Schlueter/Getty Images

Höcke condemned an attack earlier this month on a synagogue in the eastern city of Halle carried out by a lone gunman, but was accused of helping stoke the hatred with his anti-Jewish rhetoric. He has called for a “180-degree shift” in Germany’s remembrance culture of its Nazi past and has labelled the Holocaust memorial in Berlin a “monument of shame”. When a state broadcaster suggested to him recently it was hard to decipher between some of his statements and those of Adolf Hitler, Höcke angrily walked out and said he was being portrayed as “the nation’s devil”.

Mike Möhring, the CDU’s main candidate who has received death threats from neo-Nazis during the campaign, has called Höcke “a Nazi” and his and the other parties have refused to enter a coalition with the AfD.

The result in Sunday’s election is unlikely to cause any major upsets in Berlin, but it is being watched closely, not least as a gauge of the AfD’s standing.

“I am undecided,” said Astrid. “I am angry, but I have no desire to be associated with Nazis.”