By Sarah Marsh

BERLIN (Reuters) - Socialist bookstands ring the campaign rally of Germany's Left party, Trotskyites hawk newsletters and scarlet balloons stand out against the drab backdrop of high-rise apartment blocks in the autumnal drizzle.

The Left, whose old-school socialism appeals particularly in former communist East Germany, has leapt to third place in one opinion poll before the September 22 election, thanks partly to its categorical rejection of military intervention in Syria.

If the Left, polling between 8 and 10 percent, joined forces with the centre-left Social Democrats (SPD) and Greens they could match Chancellor Angela Merkel's centre-right government in strength, possibly even ousting her after the vote.

The SPD has ruled out such an alliance with the Left, which it deems too radical. But the growing clout of pragmatically minded eastern Germans within the party could open the way to a broad leftist coalition in Germany in the future, analysts say.

"The stronger the Left party is, the more peaceful and social the country is," its charismatic parliamentary leader Gregor Gysi, 65, told the rally in Marzahn, the eastern Berlin district where he won his first parliamentary seat after German reunification in 1990 and which remains a party stronghold.

The Left's strength encourages other parties, even Merkel's conservatives, to tilt in a more leftward direction, he said.

Formed in 2007 from a fusion of western-based SPD defectors and the reformed heir to East Germany's communists, the Left now boasts more members than either the Greens or Merkel's junior coalition partner, the pro-business Free Democrats (FDP).

"The Left appeals to a certain way of living in eastern Germany, whereas in the west they attract more the protest vote and appeal to those who feel the SPD is not left-wing enough," said Klaus-Peter Schoeppner of the pollster Emnid.

Amid German angst over possible U.S. air strikes on Syria, he added: "They always get a boost when war is mentioned."

No German party has been so consistently pacifist since the Greens backed military deployments during their stint in power. The Left, which has railed against military action in Syria at its campaign rallies, wants to halt arms exports, bring German peacekeeping troops home from Afghanistan and also exit NATO.

On domestic policy, like the SPD, it wants a national minimum wage and higher taxes on the rich. Unlike the SPD, it voted against euro bailouts, saying they help only the banks while inflicting painful austerity on poor Greeks and others.

Slogans on Left election posters read: "Those who want democracy must disempower the financial mafia" and "Enough drivel! A 10 euro minimum wage now!".


The SPD's centrist candidate for chancellor, Peer Steinbrueck, has rejected a "red-red-green" coalition - a strategic mistake, according to Gysi, as the Social Democrats languish far behind Merkel's conservatives in the polls.

"The SPD must realise that without us, it will never nominate a chancellor," said Gysi, a gifted and feisty orator.

But for mainstream parties the Left remains beyond the pale.

More than a third of its 76 federal lawmakers are under surveillance for possibly harbouring views - or associating with people who harbour views - that could be construed as anti-constitutional, Germany's intelligence agency said last year.

"There are still enough people who do not see the Left as a normal party because of its past, and there are indeed party members, especially in the west, who are not convinced democrats," said Oskar Niedermayer, a political scientist at Berlin's Free University.

This means a coalition with the Left at the moment could be "very dangerous for the SPD or Greens", he said.

Merkel's coalition has used the spectre of a left-left alliance as a red scare card for centrists to spurn the SPD.

The Left was long torn between an ideologically-minded wing of mostly western Germans and a more pragmatic faction of former East Germans like Gysi eager to get a shot at governing again.

However, the sidelining of Oskar Lafontaine, who had defected from the SPD and become its harshest critic, and the Left's exit from three parliaments in western Germany suggest the eastern pragmatists may be gaining the upper hand.

Georg Brozek, 78, handing out party leaflets in Marzahn, said the Left understood eastern German concerns - an important factor in a country where some in the former East still complain of discrimination and neglect 23 years after reunification.

The Left is the second strongest party, ahead of the SPD, in several eastern states.

"It's clear we don't want the old socialist model but it had positive aspects. Rents were affordable, education was good, there was more gender equality," said the retired engineer.

The Left has ruled in several regional coalitions in eastern Germany, which analysts say has forced it to take revolution off the agenda and become more realistic. In time, this could lead to a 'red-red-green' alliance, some believe.

"They (the Left) have a relatively good position on a local level and have been reliable partners in regional governments," said political scientist Gero Neugebauer. "So there is no reason to think they could not rule at a national level."

(Editing by Gareth Jones)