The battle for Germany's ruling party that will change Europe

The vote will alter the country's political landscape as it moves into the post-Merkel era - and the outcome itself is far from certain.

The CDU convention is the opening act to several regional elections in the spring, and the final federal, nationwide, vote in September that will see chancellor Angela Merkel leave office.

The leading CDU candidate, millionaire lawyer Friedrich Merz, promises to take the party back to its conservative, neoliberal roots.

The 65-year-old Merz, who tends to be blunt and often divisive, would also mean a significant change in style compared to Merkel - who sacked him as the CDU's parliamentary group leader back in 2002.

The 59-year-old Armin Laschet, state premier of North-Rhine Westphalia, Germany's heavily-populated state, is an establishment CDU figure, who portrays himself as the natural heir to Merkel.

Meanwhile, Norbert Röttgen, the chair of the Bundestag's foreign affairs committee, has run a digitally-savvy campaign, and espouses a more active foreign policy.

The 55-year-old sounds the most Europe-conscious of the three candidates, suggesting more of a continuity on the EU level.

Polls show Merz with a narrow lead, and Laschet and Röttgen neck-and-neck.

If Merz is elected, he is likely to run to be German chancellor in September. With Laschet and Röttgen, it remains more of an open question.

Complicating matters, there are two more potential chancellorship contenders: Bavarian premier Markus Söder from the Christian Social Union, the sister party to the CDU, and health minister Jens Spahn.

Varying coalitions

A lot of things can happen before the federal elections in September, depending on the pandemic, the economic fallout, and the outcome of the state elections.

With Merz at the head of the CDU, the federal campaign would be more polarised. His more right-wing brand of conservatism could make any possible coalition with the Greens more difficult. The Greens are currently polling as the second-largest party in Germany.

The CDU's current coalition partners, the Social Democrats (SPD) would want to break away from any future "Grand Coalition", which in this parliament has seen SPD support shrink, as Merkel herself took onboard more liberal and centre-left policies.

The 1,001 delegates who will gather online for the two-day convention, however, will not necessarily decide based on an election calculus, but out of a feeling that the country's strongest party should have a more typical, conservative future, after Merkel's 16 years of pragmatism at occupying the political centre-ground.

"It might be a more of a position-based decision, rather than a strategic decision," Dr Katrin Böttger, director at the Berlin-based Institute for European Politics told EUobserver.

"Delegates might think that instead of Merkel's short-term, female, softer approach, 'we want to have a strong man, and have strong opinions'," she added.

CDU delegates might feel "now it is time to follow convictions" and have a strong position in coalition talks, as they currently lead by more than 20 percentage points over the Greens, Böttger pointed out.

Coalitions talks are not expected to be easy, and Böttger estimates that would be a "good" outcome if the new government is up and running in early 2022.

Orban will be longest-serving EU leader

"The [CDU] vote is one of many steps that ultimately will define how German EU policy will look like in a year," Böttger said.

"Sooner or later we will see a polarisation of German politics, at this election or the next, and that can lead to changes on European level," Böttger added.

Böttger pointed out that Merz, if elected, is likely to be more accommodating to the positions of Germany's far-right Alternative for Germany (AfD).

Any new German leader will also be much less experienced in the European Council, the regular Brussels summit of the EU leaders, where Merkel is now the absolute veteran.

Hungary's Viktor Orban will become the longest-serving member of the European Council, closely followed by the Netherland's Mark Rutte.

The pillar of stability that Merkel represented in the European Council, whether through good or bad compromises, will be gone.

The new German leadership is also expected to be more inward-looking - especially during coalition talks - and wary of any deep-dive into European integration at the outset.

While the expectation remains for Germany to lead, Berlin itself will be figuring out its own position for a while.

"Any future CDU chancellor will thus start from a position of managing the status quo, preserving what has been achieved, maintaining the crucial relationship with the US, and not risking Germans' support for European integration," Sophia Besch and Christian Odendahl at the Centre for European Reform write in their analysis.

"Europe should not expect a Macronian reform agenda for Europe from Röttgen, nor does it need to fear a chancellor Merz (for his orthodox economic views) or Laschet (for his odd foreign policy ideas)," they added.

The CDU vote will also have an impact on the largest European party family, the European People's Party, where the CDU has also played a balancing role between Orban's increasingly far-right Fidesz plus its allies, and the more progressive wing of the EPP.

The end to Merkel's pragmatism could also change the balance in EPP as well.

The new German leader will need to establish himself in a time when democracy is more volatile than at any point in recent decades in the Western world.

Asked about a Merkel legacy, Böttger had a warning: "Nothing that has been achieved is ultimately certain, the progressive politics can be rolled back," she said, adding that this is why it is important to call out the AfD and its lies.