Even on a clear day, history hangs over Warsaw like smog. Flattened during the Nazi German wartime occupation and rebuilt during communist rule, what Poland’s capital may lack in architectural charm it makes up for with a litany of monuments, statues, plaques and shrines dedicated to collective suffering and individual sacrifice.

One lesser-known memorial is a small plaque on the wall of the Warszawa Gdańska railway station, a nondescript socialist-era building on the north side of the city. It was from here that many Poles of Jewish origin departed in the wake of the “anti-Zionist campaign” in March 1968, when cold war politics and a power struggle within the Polish Communist party led to an antisemitic propaganda campaign forcing thousands of Polish Jews to leave the country.

“Loyalty to socialist Poland and imperialist Israel is not possible simultaneously,” prime minister Józef Cyrankiewicz had declared in 1968. “Whoever wants to face these consequences in the form of emigration will not encounter any obstacle.” The plaque bears a tribute from the Polish-Jewish writer Henryk Grynberg: “For those who emigrated from Poland after March 1968 with a one-way ticket. They left behind more than they had possessed.”

In a few weeks’ time, Poland’s Jewish community will mark the 50th anniversary of the events of March 1968. They will do so in the wake of arguably the most serious crisis in Polish-Jewish relations since the fall of communism in 1989, after the passage of controversial legislation criminalising the attribution to the Polish state or Polish nation of complicity in the crimes committed by Nazi Germany during the Holocaust.

Facebook Twitter Pinterest A crowd surround a dead man on the street in the Warsaw ghetto around 1940. Photograph: Imagno/Getty Images

Although popular at home, the legislation signed last week by President Andrzej Duda has proved a diplomatic and public relations catastrophe abroad, as scholars, Holocaust survivors and friendly governments alike have lined up to voice their criticism and concerns about a potentially chilling effect on the study and understanding of the Holocaust.

The ensuing controversy has sparked a war of words between Polish and Israeli politicians, and an outpouring of antisemitic rhetoric in Poland as nationalist and pro-government media seek to portray the country as under attack from an international anti-Polish campaign orchestrated by foreign powers and Jewish advocacy groups abroad.

Ruling party officials have claimed the row has been confected by Jewish advocacy groups seeking compensation for property restitution claims. An editorial on the rightwing TV Republika website described the crisis as “a big test of loyalty for the Polish Jews whose organisations are linked personally and institutionally with American Jews”, and accused them of “too rarely and too weakly defending Poland and the Poles in the international arena”.

“They want to break us – it’s about sovereignty, truth and money,” read the cover of Sieci, a weekly that has close ties to Poland’s ruling Law and Justice party.

Speaking to the Observer, members of the Polish-Jewish community and activists involved in Polish-Jewish dialogue and reconciliation have expressed their shock and dismay at this deterioration in public discourse. While stressing that the present crisis is not comparable to that of March 1968, many said that, with their loyalties once again being called into question, the echoes of the rhetoric of the “anti-Zionist campaign” were too uncomfortable to ignore.

“We are receiving antisemitic, anti-Jewish statements on a daily basis,” said Anna Chipczyńska, president of the Jewish Community of Warsaw. “Members of the community feel that their loyalty is being questioned, that people are expecting them to take a side. Some of them also indicate the silence of friends and work colleagues in the face of these attacks, and this really hurts them.”

“In 1968 they talked about an international Zionist conspiracy; now they talk about an international anti-Polish conspiracy,” said Jan Gebert, who wrote an open letter to Polish parliamentarians on behalf of Polish Jews, expressing concern that the legislation would criminalise giving testimony about Poles who blackmailed or murdered Jews during the Holocaust. “When you’ve grown up in Polish culture, you understand that there is no fundamental difference between these two things.”

Speaking from his office in the neo-romanesque Nożyk Synagogue, Warsaw’s only Jewish place of worship to have survived the war physically intact, Poland’s chief rabbi Michael Schudrich acknowledged that the rhetoric of recent days had left some questioning their future.

“In the last week I’ve heard more young Jews think about leaving Poland than I have ever before,” he said. “They say, literally: ‘Rabbi, is it time to leave?’ That’s a challenge for the Polish government: some of their citizens no longer feel comfortable living in their country.”

Schudrich, a New Yorker with Polish roots, is credited with playing a key role in Poland’s “Jewish revival” of recent decades, having served as the country’s chief rabbi since 2004. He was also at pains to warn that inflammatory rhetoric and exaggerated claims, especially in Israel, as regards the true extent of Polish complicity in the Holocaust were helping to fuel a vicious cycle of mutual recrimination.

“What has been very disappointing to me is that we’ve re-entered a kind of a mindset where too many people are not listening to each other. Where we have been successful over the past 25 years is to have an increasing sensitivity to what hurts the other side, and what I’m seeing now is a complete lack of sensitivity, both from the Polish to the Jewish and from the Jewish to the Polish side.”

It is a point echoed by Professor Dariusz Stola, director of the Polin Museum of Polish Jews, which opened in 2013 and is seen by many as a crowning achievement of Polish-Jewish dialogue and reconciliation. “Those who condemn Poles en masse are the best friends and allies of Polish antisemites – they feed each other.”

Sitting in his office in the museum’s iron- and copper-clad structure on a site in the former Warsaw ghetto, on a street named after Mordechai Anielewicz, a leader of the 1943 Warsaw ghetto uprising, Stola argued that the recent deterioration in Polish-Jewish relations illustrates a wider deterioration in Polish society.

“It is a sign of a deterioration in the capacity to talk, and the ability to talk is the essence of democracy. If you cannot talk, you cannot reach an agreement; you can only force a solution. The erosion of language is the erosion of democracy and the path to violence.”

The question being discussed now is whether the present crisis can be resolved before the achievements of recent decades are undone entirely.

“A lot of people on the Jewish side are now saying that this was not an honest process – they feel tricked,” said Agnieszka Markiewicz, director of the Warsaw office of the American Jewish Committee, an advocacy group, and a former director of external relations at the Forum for Dialogue, a Warsaw-based NGO focusing on Polish-Jewish reconciliation.

“But it was not a trick! It was real. Poland did immense work, but now there is a risk that it will be treated as a kind of cover-up.”

“It’s a sin to let what’s happened in the last week undermine or destroy everything that we’ve built in the last 25 years, and we cannot permit that to happen,” said Schudrich.

But asked what he tells those who ask him about whether they should leave the country, the chief rabbi signalled that the legislation at the centre of the present controversy had forced him to reflect on his own future as well.

“I tell them it’s time to fight. But if it comes a time in this country where I cannot say what the truth is without fear of being imprisoned, I will leave. That time hasn’t come, and I will fight with all my heart and all my soul to make sure it doesn’t come to that.

“But I’m not hanging around here if I can’t say what the truth is.”