By Stephen Brown
BERLIN (Reuters) - Coaxed into a tub of plastic bubbles with a 19-year-old drama student, the German center-left's candidate for chancellor Peer Steinbrueck shows a sense of humor that his rival Angela Merkel would struggle to match.
But his performance taking questions from nine teenagers dressed in space suits at the Berlin campaign event also gave clues as to why the Social Democrat (SPD) is so far behind Merkel less than six months before parliamentary elections.
Steinbrueck told the students at a Berlin theatre that he likes red wine, Tolstoy novels and Lou Reed's 1972 rock hit "Walk on the Wild Side" - but revealed little else besides a razor-sharp wit.
"I don't know if I'd vote for him," said 16-year-old Timothy Stachelhaus. "I need to know more about what he stands for."
Germany shows no sign of tiring of Chancellor Merkel after her nearly eight years in office. Roughly two in three Germans approve of the job she is doing, according to recent opinion polls. Fewer than one in three is happy with Steinbrueck.
Steinbrueck performed well as finance minister in Merkel's first government, a "grand coalition" of his SPD and her conservatives which ruled from 2005 to 2009. But while he deftly handled the global financial crisis then, the 66-year-old is struggling to win over voters now.
The SPD hopes Steinbrueck's habit of speaking his mind will contrast favorably with Merkel's blandness. But so far it has only got him, and his party, into trouble.
At a congress in Bavaria on Sunday, the SPD will try to draw a line under Steinbrueck's disastrous campaign start.
The party will present a policy program that promises to address the social cost of the Merkel years. It includes more spending on education, equal pay for women, a nationwide minimum wage, affordable housing and measures to "tame" financial markets and crack down on tax havens.
"More 'us' and less 'me'," is the new slogan of Germany's oldest party, which celebrates its 150th anniversary this year. German media joke that the real message behind the SPD's motto is "less Steinbrueck".
Part of the problem is that Steinbrueck, a moderate who backed former SPD Chancellor Gerhard Schroeder's controversial overhaul of the welfare state, has had to bend over backwards in recent months to satisfy left-wingers in his party.
He has agreed, for example, to raise the top level of income tax to 49 percent from 45. And he regularly rails in his speeches against bankers and income inequality.
"Merkel talks about regulating the financial markets but does nothing about it. Peer Steinbrueck would do it," said Sascha Vogt, head of the SPD's leftist youth wing Jusos.
But his leftward shift has come at a price, diluting his image as a straight talker and confusing voters, who now question what he stands for.
Selected last September after the rest of the SPD "troika" - former foreign minister Frank-Walter Steinmeier and party chairman Sigmar Gabriel - ruled themselves out, Steinbrueck has long had a reputation for shooting from the hip.
As finance minister he offended Germany's neighbors in 2009 in a row over tax havens by likening the Swiss to "Indians" running scared from the cavalry.
Tall, bespectacled and jowly with grey suits and a paisley scarf, Steinbrueck can appear pedantic and aloof. Soon after he was named candidate, he caused offence with snobbish remarks about cheap wine and about chancellors being underpaid.
More damaging still were revelations he had earned 1.25 million euros ($1.6 million) as an after-dinner speaker since leaving the government in 2009. Many of the speeches were to the same financial institutions he now promises to "tame".
"He has no political instinct," said a Merkel aide. "That is the difference between any old MP and a chancellor candidate."
In a recent Forsa poll only 24 percent of respondents thought Steinbrueck diplomatic enough to be chancellor. SPD leaders know his style has risks but are convinced it lends him an air of authenticity. "I wouldn't like him to avoid speaking his mind because it would undermine his appeal," a senior SPD official said.
Some media commentators like his straight-talking style, with the top-selling Bild newspaper saying in a column it "could be his strongest trump card" against an "often nebulous" Merkel.
Microphone in hand in a Berlin auditorium last week, the SPD candidate had his audience in stitches. Academics who heard him at the London School of Economics in February called him a "funny guy" - not a description usually attached to Merkel, who leads the Christian Democrats.
This has not prevented a precipitous decline in Steinbrueck's ratings since mid-2011, when he was briefly Germany's most popular politician.
"It was certainly very entertaining," said Moritz Steinle, a German student at the LSE. "But I still think for the future of Germany the Christian Democrats are probably a better choice."
The SPD knows Merkel's soaring domestic reputation thanks to her euro crisis leadership will make her hard to beat. "The woman is a cult," shrugged a top campaign aide to Steinbrueck.
The SPD campaign strategy, inspired by Barack Obama's U.S. Democrats, is to go "grass roots". They are knocking on doors and vowing to mobilize supporters like they did when Schroeder won a decade-and-a-half ago. Four years ago, the party had its worst election result in the post-war period with 23 percent.
Steinbrueck has said he will avoid big speeches, instead focusing on "living-room chats" and intimate events like the Berlin studio theatre event. The hope is that he will come across less as aloof in person than in the media's glare.
Humanizing Steinbrueck is one of the party's big challenges. But he has ruled out using his wife and daughters to soften his image and they will not appear on stage at Sunday's congress in the city of Augsburg.
"My impression is that people really haven't understood yet why he wants to be chancellor," said another SPD strategist.
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(Additional reporting by Holger Hansen and Noah Barkin in Berlin, Mark John in Paris and Michelle Martin in London; editing by David Stamp)