The Pirate Party, whose eclectic campaign is focused on Internet policies and broader participation in the political debate, stormed onto the German political scene last year by seizing 8.9 per cent of votes for Berlin's city assembly.
Its membership has nearly doubled in a year to around 21,600 members, and the Pirates entered their second state parliament after taking 7.4 per cent of the vote in the tiny state of Saarland. Germany has 16 federal states.
The main parties view as incapable of governing and dismiss it as a protest movement with no real political platform.
Yet, the upstart party outshone both the Greens and Chancellor Angela Merkel's Free Democrat (FDP) allies who crashed out of the assembly with just 1.2 per cent.
"People voted for us because we offer something new and fresh, and because we are completely normal people who engage citizens," Jasmin Maurer, 22, regional head of the Pirates, told German television.
"And what also moved people to vote for the Pirates was our focus on more civil rights, more democracy and transparency."
Their Berlin success was initially viewed as a one-off.
But they are gaining momentum, and pollsters predict they have good chances of clearing the five-per cent hurdle to win seats in state assemblies in Schleswig-Holstein and North Rhine-Westphalia (NRW) in elections in May.
"They are on the upswing and politics is a very emotional business," said Klaus Schoeppner, head of polling group Emnid. "For both the coming regional elections, they have good chances of getting in."
Joachim Paul, 54, a leader of the Pirates in NRW, said membership there had already risen after Sunday's electoral success in Saarland. "This is a fantastic campaign basis for us and I hope there is a chain reaction in the vote here," he said.
Anything but the mainstream
The Pirate Party first emerged in Sweden six years ago to campaign for reform of copyright and better privacy in the Internet age. When the German chapter was founded months later, it was initially seen by some as a group for computer nerds.
The Pirates may still be led by their technology-savvy core membership, but they have since broadened their agenda to include issues such as establishing a minimum wage and providing voters with more opportunities to decide on the issues of the day, offering a new alternative to musty mainstream politics.
Pollsters said the Pirates, whose members have an average age of 31, had mostly gained the votes of people fed up with established parties. An exit poll showed 85 per cent of the Pirates' voters in Saarland did so out of disillusionment.
"It's not a vote for something because people don't really know what they stand for other than a freer Internet as their programme is so basic," said Manfred Guellner, head of Forsa pollsters. "At the moment, they are living off the fact they are the beneficiaries of people's frustration with other parties."
"The Pirates voters come from all layers of society, they are not only young nor middle-aged. They're abandoning all parties from the FDP to the Left."
The Pirates have in many ways usurped the Greens as the country's impudent alternative to the mainstream. "The Greens had this role for a long time, but now their leaders are in their 50s and it is a very established party," said Schoeppner.
That other parties see the Pirates as a serious threat nationwide was demonstrated on Monday by the increasingly combative stance they struck at headquarters.
"My goal is to keep the Pirates out of Bundestag," said Andrea Nahles, the General Secretary of the centre-left Social Democrats (SPD). "They are political competition and are causing a lot of trouble for parties in the centre ground."
A problem arising from the Pirates' surge may be that it becomes more problematic for parties to form coalitions in an increasingly fragmented landscape, leaving a "Grand Coalition" of the two major parties one of the only options.
According to the latest national polls, some 20 per cent of the vote would go to parties such as the Pirates. That would thus make it more difficult to form a centre-left or centre-right coalition.
Whether or not the Pirates become a mainstay of German politics now depends on how they perform in parliament.
"They must learn the art of politics and offer answers, like the Greens were forced to," said Forsa's Guellner, referring to the Greens' ascent from a single-issue environmental party in the 1980s portrayed as tree-hugging hippies to become a partner in the federal government.
But their mere presence on the political scene has already led other parties to lend more focus to issues such as Internet policies, just as the Greens drew attention to the environment.
Chancellor Angela Merkel said her party was well aware the Pirates were becoming a key player.
"We have set up an Internet group within the CDU," she said on Monday. "We have to be aware of the Pirates." — Reuters