By Erik Kirschbaum
BERLIN (Reuters) - Germany's Pirates, a party that came from nowhere to be a major political force, are suffering a dramatic reversal of fortune that could harm Chancellor Angela Merkel's 2013 re-election chances.
After surging ahead of the Free Democrats (FDP), Left Party and Greens to become Germany's third strongest party, polling 13 percent in April, the Pirates have fallen back to 4 percent.
Their drop below the 5 percent threshold needed for seats in parliament could mean the centre-left Social Democrats (SPD) and Greens recover enough votes to form a majority next year and oust Merkel.
"The Pirates raised expectations that couldn't be fulfilled," said Matthias Jung, head of pollsters the Electoral Research Group. "The speed of their decline has a lot to do with the way they've been quarrelling in public."
The Pirates are a band of self-confessed nerds who campaign on an eclectic platform of free Internet downloads, data protection, free public transport and legalizing drugs.
Their anti-establishment stance appealed to voters across the spectrum but particularly from the left, meaning the SPD and Greens would gain the most votes from former Pirates supporters.
As well as retrieving lost votes, they could also benefit indirectly from Germany's coalition arithmetic.
If the Pirates and the FDP fail to win any seats next September, the popular vote needed for a parliamentary majority could fall to as low as 43-45 percent instead of the usual 47-48 percent when five or six parties are in parliament.
With the SPD and Greens currently scoring 42 percent or more in polls, this would put them in reach of power.
Merkel's conservatives are currently at 39 percent, up from 33.8 percent in the 2009 election. Their FDP junior coalition partners are at 4 percent, down from 14.6 percent in 2009 and below the threshold for survival in parliament. The Left is also on the brink at about 6 percent.
"The chances of an SPD-Greens coalition are definitely higher if the Pirates and FDP fail to win 5 percent," said Everhard Holtmann, political scientist at Halle University. "If the Pirates get in, the odds of a 'grand coalition' (of conservatives and the SPD) are greater."
A Merkel adviser told Reuters during the Pirates' speedy ascent earlier this year that a collapse of support for the upstarts was one of the conservatives' biggest worries.
"DISSOLVING IN PUBLIC"
"I'm not surprised support for the Pirates is eroding," said Holtmann. "But I am surprised how quickly they're imploding."
The Pirates arrived on the political scene a year ago with a shock 8.9 percent in a local Berlin election.
But their support declined as fast as it grew, partly due to of a lack of coherent policies on most issues, but also because of bizarre TV appearances by some leading Pirates and the overall chaos of the organization.
"They don't have any positions in important areas like economics, foreign policy and social issues. They appear to be dissolving in public before our eyes," said Holtmann.
Two party leaders announced their resignations last Friday in protest at the party's campaign manager Johannes Ponander, an eccentric 34-year-old student/actor who has boasted about living off the state most of his adult life.
The Pirates have also been accused of hypocrisy. Julia Schramm, a party leader, refused to allow her book "Click me - confessions of an Internet exhibitionist" to be released for free on the Internet.
Other protest parties that have come and gone in Germany in recent decades include the far-right "Republikaner", the "STATT Partei" (Instead Party) in Hamburg, and a party led by a conservative judge named Ronald Schill that surged to 19 percent in Hamburg in 2001.
The pollster Jung estimates the Pirates might have a "hard-core potential of 2 to 3 percent" of the electorate.
"Parties like this that serve as a lightning rod for protest might be able to latch on to the short-term frustration and ride on a wave of media interest for a while," he said.
"But then when they face the spotlight of everyday political stress they often lose their appeal."
(Editing by Robin Pomeroy)