BERLIN — When a German banker and former government official spoke publicly about a “Jewish gene,” when he attacked Islam as a source of violence and stunted development and when he espoused genetic theories that evoked the fright of the Nazi past, the political leadership here quickly condemned him as racist and called for him to be fired.

But the banker, Thilo Sarrazin, an executive with the central bank, or Bundesbank, and a former Berlin finance minister, has not emerged as the marginalized hate-monger that the initial condemnation suggested. His book, “Germany Does Away With Itself,” which laments the growing number of Muslim immigrants, contending that they are “dumbing down” society, was released Monday and is already in its fourth printing, with sales expected to exceed 150,000 copies, according to his publisher.

Sarrazin has set off a painful public discussion here that has highlighted one of the nation’s most vexing challenges: How to overcome what is widely seen as a failed immigration policy that over decades has done little to support and help integrate the nearly 20 percent of the population who have an immigrant background. It is a policy that has also stoked anti-Islamic sentiment and hostility.

The sensation of Sarrazin’s book and his unrepentant posture have also provoked something less tangible but perhaps more troublesome for policy makers here eager to keep the radical right from gaining a foothold as they have in other parts of Europe. Under the cover of speaking truth to power, Sarrazin has tried to legitimize hate speech, his critics say.

One of the most telling signs of the growing distance between native Germans and immigrants, officials here said, is the observation that the grandchildren of immigrants are less likely to integrate into German society and less likely to even apply for citizenship compared with members of previous generations, creating an ethnic underclass in education and employment. Residents from immigrant families are twice as likely as ethnic Germans to be unemployed.

“This issue is now more important for Germany than the economy,” said Wolfgang Nowak, former senior adviser to the previous chancellor, Gerhard Schroeder, and the head of Deutsche Bank’s International Forum.

Nowak argues that Sarrazin has done his country a favor by forcing the topic to the top of the political agenda and crashing through the barriers of political correctness.

“The condemnation of his book is an automatic reflex of a generation raised after Hitler,” he said.

Even some who found his approach offensive said that Sarrazin had “addressed a problem that will remain long after the waves of outrage have subsided: the enormous integration deficit of the Muslim minority in Germany, or at least of disturbingly large parts of it,” said an article in the center-left newspaper Sueddeutsche Zeitung.

In a newspaper interview published the day before the book was released, Sarrazin also spoke of a Jewish gene, a reference to recent studies showing that Jews share many genes inherited from the ancestral population that lived in the Middle East long ago. He was criticized by everyone, including the chancellor, Angela Merkel.

His party wants to kick him out, and the bank is considering firing him. On Thursday, the board of the bank voted to ask Germany’s president to dismiss Sarrazin from the board, and Merkel applauded the decision.

Sarrazin’s stance, and the traction it has gained, has alarmed many, in part because he is not a member of the extreme right but a longtime member of the center-left Social Democrats and the former top financial official for the city of Berlin, one of the centers of the immigrant community.

“If he were an extremist, no one would pay attention,” said Hatice Akyuen, a writer who has debated Sarrazin and condemned his theories of the innate inferiority of immigrants. “He is a Social Democrat. You cannot do what he is doing, not in this country. You cannot give this kind of thinking a democratic base.”

Akyuen, whose father came to Germany from Turkey in 1969 to work as a miner, said that the debate often came down to the difference between integration, which she said immigrants and their families accept, even desire, and assimilation, which they reject.

Maxim Biller, whose own family moved to Germany from Prague when he was a child, said, “The only chance for acceptance in German society is total assimilation, don’t hold onto our traditions.”

Sarrazin, who wears small, round glasses and has a stern face topped by a shock of mostly white hair, said that he wanted to highlight what he described as the drain on Germany by an immigrant class.

In his book, he criticized Islam and blamed Muslim immigrants for refusing to integrate. He also blamed Germany for being too generous with its social benefits, which he said attracted immigrants looking for handouts.

“No other religion in Europe is so demanding and no other migration group depends so much on the social welfare state and is so much connected to criminality,” he wrote in one passage.

Germany has had a difficult time coming to terms with its immigrant population. Next year will be the 50th anniversary of the guest-worker program for migrants, mostly Turks. Originally, the plan was for the workers to return, although that idea evaporated in the 1970s when Germany allowed workers’ families to move here, said Gunter Piening, an official who deals with integration and migration issues for Berlin.

“The German philosophy was, ‘We are not a migration country,”’ he said. “There were migrants, but there was no migrant policy.”

It was only in 2005 that Germany acknowledged that it had become a destination country, a shift that was not accompanied by a practical plan, Piening said. That has slowly begun to change, he said.

Recently, for example, Berlin revamped its secondary education system because it recognized that children of immigrants were “getting an education which was good for nothing, a dead end.” Steps have been taken to also allow Muslims to be buried without coffins — the custom for Muslims is to be wrapped in a shroud — a small measure if ultimately adopted but one that would nonetheless help make Muslims feel more welcome, Piening said.

It is not, however, entirely benevolent as German officials recognize that they will need immigrants in coming years. According to a recent survey by the German Chambers of Industry and Commerce there will be 6 million fewer Germans of working age by 2030.

© 2010 The New York Times Company