The most popular symbol of the radical left in Germany is an avowed anti-capitalist and a firm believer in collective property. He takes down neo-Nazis with the same bouncy energy as he tackles property speculators.

Books expounding his views, running at several volumes, top the German bestseller charts; posters bearing his face are currently plastered all over the country’s cities.

His only liability, in terms of electoral optics, could be a fatal addiction to booze-filled pralines – and the marsupial pouch in which he keeps his copy of Mao’s red book.

The Kangaroo Chronicles, a quartet of comic novels by slam poet Marc-Uwe Kling that has sold millions of copies in Germany over the last 10 years, is a classic man-meets-beast buddy story in the vein of Seth MacFarlane’s 2012 comedy Ted – only that its animal protagonist is mainly vulgar in the Marxist rather than the foul-mouthed sense.

The communist kangaroo lives in a flatshare in the heart of counter-cultural Berlin with Marc-Uwe, a bohemian slacker whose anarchist principles are “so mild, he might as well join the [centre-left] SPD”.

A big-budget film based on the cult books opened in German cinemas last week, seemingly showing that hairy lefties stuck in 1970s dogmas don’t just trigger feelings of warm affection in the political bubbles of the big cities, but can also have mainstream appeal.

As if to emphasise that message, a day before the movie’s premiere parliamentarians in the eastern state of Thuringia re-elected the only state premier for the leftwing party Die Linke – the popular and widely respected Bodo Ramelow.

And throughout the week, several pollsters have predicted that a three-way coalition between the Greens, the Social Democrats and Die Linke could yield a governing majority at the next federal elections, which would be the first time the successor party to the East German Socialist Unity party would enter the national government since the fall of the Berlin Wall.

Yet Kling’s cult hit also demonstrates exactly why the kangaroo, an avowed political populist, is also the worst nightmare for a leftwing party with an eye on the seats of power.

The film, directed by Swiss filmmaker Dani Levy, shows the communist marsupial team up with Berlin locals against Jörg Dwigs, a Trump-style property tycoon and founder of the fictional AzD (“Alternative to democracy”) party: a classic “the people v the elite” narrative, which the German far left has found more difficult to adopt than its counterparts in Britain, America or Southern Europe.

“The German left is still nervous about using populist rhetoric,” said Jürgen Lang, a political scientist and journalist who specialises in the history of Die Linke. “There’s a fear that once you go down the road of talking about ‘the people’, you are in an arena where the far right will beat you at that game.”

Even in a left party notoriously divided between libertarian, orthodox anti-capitalist and Trotskyist wings, said Lang, “there are factions that hold populist positions, but there isn’t really a populist faction”.

Facebook Twitter Pinterest Bodo Ramelow at a cabinet meeting of the Thuringian state parliament on 4 March. Photograph: Martin Schutt/AFP via Getty Images

Aufstehen! (Get Up!), an attempt to manufacture a left wing populist grassroots movement along the lines of France’s gilets jeunes led by charismatic Die Linke politician Sahra Wagenknecht, disintegrated barely a year into its existence.

Bodo Ramelow hails from Die Linke’s party branches in the east. Unlike the far-right Alternative für Deutschland (AfD), which is at its most rabidly nationalistic in the states that used to make up the German Democratic Republic, left party politicians in the same regions have shown themselves more interested in forming governing alliances than theorising about world revolution.

“Ramelow and his people have, in the past few years, shown us evidence that they are capable of accident-free, pragmatic and solid governance,” wrote Der Spiegel this week.

In the wake of the controversial vote in Thuringia, which initially saw Merkel’s centre-right party vote with the AfD in order to oust Ramelow, the centre-left SPD’s general secretary, Lars Klingbeil, said his party had “never been so ready for a pact [with their far-left rivals] as we are now”.

For there to be a realistic possibility of a Green-Red-Red coalition after the next German elections, scheduled for 2021, the Left party will have to prove that it is capable of containing its Kangaroo-ish tendencies, however.

A video that surfaced in Germany media last week briefly seemed to threaten Ramelow’s chances of being re-elected.

Filmed at a Die Linke strategy conference in the western town of Kassel, it showed one participant argue that “once we have shot the 1% of the rich, we will still want to heat our homes and travel”.

Rather than criticising the comments, the party’s co-leader Bernd Riexinger responded with an attempt at a joke: “We are not shooting them, but we will make them do some useful work.” Ramelow was one of the first to criticise the comments when the video emerged, calling them “unacceptable”.

Anyone who sees The Kangaroo Chronicles will know that a broad-church German left setting its eyes on government in 2021 will meet similar turbulence along the way. “We can be friends,” the movie’s marsupial hero says to his more moderate political ally, before whispering to himself: “Until after the revolution, anyway.”