For 13 years the pretty German city of Lüneberg has been the backdrop for Rote Rosen (Red Roses), a soft-focus tele-novella about 40-somethings finding love among medieval buildings.

On Saturday a very different soap opera comes to town. Our leading lady Annegret Kramp-Karrenbauer takes to the election stage in Lüneberg in her first campaign as leader of the ruling Christian Democratic Union (CDU).

Six months after taking over from Angela Merkel, the new CDU boss has framed the EU election as a make-or-break moment for mainstream European parties like hers: take seriously voter concerns – on security, defence, climate change – or risk a mass defection to populist forces. But it’s also a domestic bellwether for Germany’s newest political leader.

“The mood towards Europe is very good but European elections were always a reflex towards the national situation,” said Kramp-Karrenbauer. “Playing a role here is how we’re not viewed utterly positively.”

The CDU party programme backs a European army within the decade and rejects common EU dole payments or anything else that looks like a slippery slope to a so-called “Transfer union”, bankrolled by Berlin. The CDU wants to upgrade Europol into a European FBI, and transform Frontex into a real border police, applying unified EU asylum laws to ensure greater migrant burden-sharing.

While the CDU is steady at 30 per cent, according to a public television poll, the Social Democrat (SPD) vote has collapsed 10 points to just 17 per cent. The far-right Alternative für Deutschland (AfD) is on course to gain five points to 12 per cent but the Greens could be the big winner as polls predict a doubling of its 2014 EU election result to almost 20 per cent.

‘Fruitful confrontation’

For many Germans, more interesting than the EU election is what comes next at home. The SPD, as it slides in polls, is becoming a less predictable grand coalition partner in Berlin. Eastern state elections in the autumn could see both the SPD and CDU humbled by a further AfD surge.

Germany’s economy is cooling off, along with its closest partner across the Rhine. After two years watching his proposals go nowhere, French president Emmanuel Macron, with a slightly malicious air, has promised a more “fruitful confrontation” with Berlin. “We have to leave this narrative that everything is great and we are such great friends,” an unnamed Macron adviser tells Saturday’s Der Spiegel magazine.

All of this comes as Kramp-Karrenbauer adjusts to an untested power-share with Merkel. While the chancellor has vowed to serve out fully her fourth and last term, Kramp-Karrenbauer has fuelled rather than dampened speculation by dodging a question on whether she would ditch Merkel if required.

The CDU leader said she was not working towards “wilful change” in the chancellery and that she and Merkel agreed that a shift, if and when it happened, would be a mutual decision.

Party mood

“I don’t get up every morning with a saw in my hand to march to the chancellery and saw at Angela Merkel’s chair,” the CDU leader insisted on Friday.

Both women know their political futures hinge on looming election results and the consequent internal party mood. While Merkel enjoys the positive prestige of power, including the prospect of leading Germany’s EU presidency next year, the CDU leader has the less glamorous – and less visible – backroom political work.

Just over a third of Germans are satisfied with the new CDU leader, according to one poll, while another found just 11 per cent of Germans can imagine the 56-year-old moving into the chancellery.

All of this only serves to increase suspense in Berlin over what happens when power and loyalty come into conflict in this real-life political soap opera.