BERLIN — Pirates are capturing Germany's political system.
The party with the outlaw name started as a marginal club of computer nerds and hackers demanding online freedom, but its appeal as an antiestablishment movement has lured many young voters to the ballot boxes, catapulting it into two state parliaments in less than a year.
The all-volunteer Pirates offer little ideology and focus on promoting their flagship policies of near-total transparency and an unrestricted Internet. But polls show them as the country's third-strongest political force, leapfrogging over more established parties.
The tremendous success has doubled the Pirates' membership to 25,000, but it also has handed them a crucial challenge set to dominate its convention starting Saturday: A party founded as a rebellious upstart must reckon with its new political power and its promise of a voice for all its members.
About 1,500 members gathered in the northern Germany city Neumuenster to discuss the group's growth. New polls predicted it would win seats in two more state legislatures in May, with forecasters expecting it to secure about 9 percent of the vote in both states.
"Many vote for the Pirates as a sign of protest. It is not directed against democracy, but it's based on the unhappiness with the functioning of the established parties," said Alexander Hensel, a political scientist who studies the Pirates at the Goettingen Institute for Democracy Research.
Analysts say that despite the nation's robust economy and low unemployment, many Germans are disenchanted with the established parties, fueled by outrage over seeing the government bailing out banks and businesses to save the economy from collapsing in the wake of the financial crisis.
Thousands in Germany took to the streets last year in rallies during the worldwide Occupy movement, but it has now all but fizzled out — with the Pirates appearing to inherit the votes of the disenchanted.
While the mainstream parties in Europe's biggest economy are struggling to come up with a response to the continent's debt crisis, the Pirates cheerfully admit they have no answers. Nor do they have a stance on whether German troops should continue to fight in Afghanistan.
But many voters welcome their blunt acknowledgment as a sign of honesty in the political arena. Instead of taking a stand on the pressing issues that more mainstream parties are forced to address, the Pirates speak up against copyright laws, demand free public transportation, and say every citizen should be paid a basic income without having to work.
"The Pirates are elected less because of what they stand for than by disappointment with the established parties and for their unconventional methods," Hensel said.
The party's core pledge of transparency and participation — live transmission of all meetings and the online involvement of all party members in its decisions, countless Twitter debates and email chains — is reaching the limit of feasibility as the number of party members has mushroomed.
The question is: Will the Pirates change Germany's political system, or will the system crack the Pirates?
Hensel said the growing volunteer party will be challenged in its organization and leadership.
Its outgoing managing director, Marina Weisband, 24, collapsed last week between two TV appearances.