“That important step away from the idea of threatening jobs, threatening development, has been taken in Germany,” Mr. Fridolin said in a recent interview. “The party is a more interesting alternative for larger groups in society, not just for people studying environmental policy at university.”

The mass killings in Norway in July riveted attention on the strength of right-wing populist parties across Europe, but particularly in Scandinavia. Yet with far fewer headlines, the Green Party in Sweden won more votes in last year’s parliamentary election than the far-right Sweden Democrats, taking 7.3 percent of the vote compared with 5.7 percent for the nationalists.

In Germany, the question is now whether the Greens sustain, or even build, on their recent advances. The party was buoyed by outrage over the Fukushima Daiichi nuclear power plant disaster in Japan, but it has fallen slightly in polls since. Still, the party could serve as a model for the postindustrial left in Europe and, perhaps, around the world.

It is a long way from the German party’s founding in 1980, when middle-class voters saw the Greens as radicals, heirs to the 1968 student protest movement or even the left-wing terrorists of the Red Army Faction. “People spat on my father when he went door to door,” said Milena Oschmann, the daughter of leading party members in the city of Kiel, Germany. She now works for the party, splitting her time between Parliament and the local office in Berlin’s Neukölln neighborhood.

Ms. Oschmann, 27, described how the party had played host in Berlin to visiting Greens from Greece, Taiwan and Japan as well as Sweden and Australia. In her sports jacket and ballet slippers, a Sony Vaio laptop balanced on her knees during a local meeting in Neukölln, Ms. Oschmann would be right at home on Capitol Hill. She studied politics in Bremen, Germany, and in London before moving to Berlin, a representative of the new generation of Green politicians who have left the beard-and-sandals stereotype behind.

While the Fukushima disaster is often credited with helping the Greens’ surge in Germany, their initial jolt in support in Baden-Württemberg came from the party’s opposition to a multibillion-dollar rail project known as Stuttgart 21 that involved tearing down portions of an old station and downing hundreds of old trees. “They’re covering both sides of the street, serving the deep conservative instincts of Germany for no change,” said Mr. Joffe, the newspaper publisher. “Protecting nature, slowing down growth, slowing down industrialization, is actually a conservative agenda.”