NOTHING is more fun for German political junkies than inventing names for exotic potential coalitions. The latest is a “pepper coalition”: Social Democrats (reds), Greens and the (orange) Pirate Party. This entered the lexicon when the Pirates took 8.9% of the vote in Berlin's election last month, securing 15 seats in its legislature, their first at state level. Nationally, the polls now suggest, the Pirates could yet displace the Free Democrats, the junior partner in Angela Merkel's coalition, as the fifth party in the Bundestag. If that happened, reds and greens might not be able to govern together without them.

It is hard to know whether to take the Pirates seriously or expect them to wilt. Although founded in Sweden, the party is most at home in Berlin, a hub for university-trained “creatives”. Their spark comes from the internet, which the Pirates think will make the world a better place so long as companies and the state get out of the way. They got a German boost from their 2009 campaign against a government bid to block child-pornographic websites.

What may give the Pirates staying power is their position as the party for people who dislike traditional politics. A proliferation of non-voters and protest movements suggests there are plenty of such people. Former non-voters were the Pirates' main source of votes in Berlin. Next were voters who had previously supported the Greens, the “anti-party party” of 30 years ago. Pirate supporters “grew up with green values,” says Uwe Jun, a political scientist at the University of Trier, but the Greens are now “an established, normal party”.

That is the last thing the Pirates want to be. Andreas Baum, who as head of their Berlin caucus is entitled to an official car, wants to trade it in for a fleet of bicycles. The Pirates want members to be in charge of their party and, eventually, citizens to command the government. They set store by “liquid feedback”, an internet-based method of discovering members' views. This helped to produce a resolution that the government should not collect data about a person's gender, a private matter that can change. By law, such decisions cannot bind the party. But Pirate leaders ignore them at their peril. They are “messengers and administrators,” says Fabio Reinhardt, a Pirate in the Berlin legislature.

Yet ambivalence about politics can also be a weakness. The killer instinct is missing. “It's important to say, ‘I don't really want to do politics but somebody has to,'” if you want to be nominated, says Mr Reinhardt. The party was slow to exploit revelations that the Bavarian government had, perhaps illegally, tapped a drug suspect's computer. The Pirates benefit from a backlash against “professionalisation” of politics, but voters may tire of amateurs.

Then there is the question of how the values of 4,600 free-spirited users of liquid feedback mesh with those of most voters. Internet culture is “very liberal, even leaning toward anarchism,” says Aleks Lessmann, a Bavarian Pirate leader. Pirates are peaceable radicals, hoping to perfect democracy, not to overturn it. But their politics are not mainstream. How many Germans support civil unions for three people or more? Or think everyone is entitled to a state income, with no need to work? Pirates are passionate about copyright (against) and privacy (for) but have little to say about foreign policy or the euro.

Berlin's Pirates have joined a world of lobbyists and constituents' gripes. They want to promote openness and citizens' participation, in part by making referendums binding. Will they count in the 2013 federal election? The trick will be to become political but remain piratical.