Many polls indicate that in the national elections scheduled for May 6, Golden Dawn may surpass the 3 percent threshold needed to enter Parliament. The group has been campaigning on the streets, something that mainstream politicians have avoided for fear of angry reactions by voters who blame them for Greece’s economic collapse.

But even if Golden Dawn fails to enter Parliament, it has already had an impact on the broader political debate. In response to the fears over immigration and rising crime, Greece’s two leading parties — the Socialist Party and the center-right New Democracy Party — have also tapped into nationalist sentiment and are tacking hard right in a campaign in which immigration has become as central as the economy.

Experts say the group is thriving where the Greek state seems absent, the most virulent sign of how the economic collapse has empowered fringe groups while eroding the political mainstream, a situation that some Greek news outlets have begun comparing to Weimar Germany.

“Greek society at this point is a laboratory of extreme-right-wing evolution,” said Nicos Demertzis, a political scientist at the University of Athens. “We are going through an unprecedented financial crisis; we are a fragmented society without strong civil associations” and with “generalized corruption in all the administration levels.”

With what critics say is a poorly policed border with Turkey, Greece is seen as an entry point for illegal immigrants, some of them asylum seekers but most intent on moving to more promising economic terrain in Northern and Western Europe. But many of the immigrants remain in Greece or are returned there after being deported from other countries in Europe. This has stoked fears here of an onslaught of illegal immigrants, who economists say bear little or no responsibility for Greece’s economic troubles but who make easy scapegoats for politicians across the spectrum.