It is a measure of the influence of Angela Merkel that the German election campaign may be decided on which candidate can appear most like her.

But when 66 million voters go to the polls tomorrow, no one is expecting that the winner will regally retain power for 16 years.

German politics have been fragmenting. The big centre left and centre right parties, the SPD and CDU/CSU, used to regularly score around 35% of the vote, guaranteeing a long period of postwar stability.

But both parties have been hemorrhaging support in recent years. The Greens, the Left Party, and the far right AfD have all been attracting voters, and pulling them away from the big parties (in the 2017 European Parliament elections, the Greens won one million votes from CDU/CSU supporters).

That means this election has been harder to call, and a new government will be harder to construct after the votes have been counted.

Most analysts predict a three-way coalition for the first time since the Second World War.

German Chancellor Angela Merkel at a CDU-CSU rally yesterday

The make-up of the coalition will not necessarily guarantee stability or the fluent passing of legislation. That has spooked markets and unsettled some EU member states, who have relied on a strong and stable Germany to restore nerves in an increasingly turbulent world.

Some analysts believe voters have not fully realised that the reassuring calm of the Merkel years are over. As mentioned above, opinion polls have shown it is the Merkel-like potential of the two main candidates for Chancellor which has motivated voters.

"There's actually a lot at stake at this election," says Dr Leonce Roth, a political scientist at the University of Cologne. "There is the fragmentation of the party system, a lot of things which we are not used to.

"All this was very clear from the beginning and in a sense, nobody cared. Just look at the fluctuations of the votes: the CDU has lost roughly 50% of their support, which has never happened before. Yet the population is mainly interested in the abilities of the candidates."

Olaf Scholz is the candidate most tipped to be Chancellor. A former mayor of Hamburg, he has been finance minister in the outgoing SPD/CDU grand coalition, and has presented himself as the Merkel continuity candidate, a competent and calm figure, even though he is from the opposite side of the spectrum.

Olaf Scholz from the Social Democrats is hoping to be Germany's next chancellor

The CDU's chosen candidate Armin Laschet, the premier of North Rhine-Westphalia, has had a dismal election campaign, failing to connect with voters and seeing his ratings slump alarmingly when he was captured on camera laughing during a visit to a flood zone during this summer's deadly flooding.

That he might be seen as an unserious candidate is a reflection of the anxieties that German voters are feeling.

Under Merkel’s tenure, Germany’s GDP tripled as the country enjoyed an export and manufacturing boom, in part due to the rising spending power of China but also to Germany’s geographical location in the centre of Europe, with the cheap automotive labour and supply chains on tap from the neighbours.

The Greens will certainly moderate their messaging on foreign policy if the door to power is ajar.

Berlin was the de facto epicentre of the European universe, dispensing both largesse by way of the bailout and Covid recovery funds, but in turn insisting on being primus inter pares when it came to lecturing others on fiscal rigour.

But the pandemic has unsettled that self image. Germany responded well in the first wave, but poorly in the second and third waves.

The country’s bureaucratic and overly cautious approach to health and data systems saw Germany fall behind in the vaccinations league table (in the early weeks of the roll-out, vaccination centres would routinely close for the weekend).

As such, the economic recovery has not been as robust as businesses were expecting.

A restaurant in Berlin, Germany during the pandemic

The new Chancellor will face lingering Covid difficulties, especially if there is a fourth wave, but there are graver challenges ahead.

As a major exporter, Germany is acutely exposed to the current supply chain issues, not to mention semiconductor shortages when it comes to the car industry.

There is also the demographic upheaval in the coming years. Germany spends 30% of the federal budget on pensions, and over the next decade the country’s baby boomers will retire, meaning a major pensions crunch is looming.

Germany will also face a gruelling and expensive overhaul of its economy in order to reach its target of being carbon neutral by 2045.

The country has struggled to develop sufficient renewables and, following the Fukushima catastrophe in Japan, has turned away from nuclear energy.

Taking a more principled stand on China and Russia will also be difficult if the next Chancellor continues Merkel's policy of using kid gloves when democratic values are threatened within Europe itself.

Businesses already struggling to emerge from the pandemic are worried that they will face a decade of new carbon-related regulations.

Germany also needs to undergo a digital transformation both in the public and private sectors, as anyone who has tried to make a smartphone transaction using a credit card or PayPal will confirm.

There will also be major defence expenditure needs as Berlin figures out how to replace its ageing fleet of Tornado fighter jets.

A key feature in the election debate is how Germany is going to pay for all these big outlays, but when much of the back and forth during the campaign has been about which candidate offers Merkel-style reassurance, analysts wonder if voters and parties have really got to grips with the challenges that lie ahead.

The SPD and Greens are broadly pushing tax increases on the rich (some of the plans would have huge implications for high earners), while the CDU and Liberal Democrats are resisting an increase in the tax burden.

The new Chancellor will have to coordinate their approach to a major review of the EU’s fiscal rules, which is due once the Covid-related exemptions and relaxations of the Stability and Growth Pact have been lifted.

If Germany decides its big challenges need a less orthodox attitude to debt and deficits, not to mention the country’s constitutional debt brake, the fear is that could encourage other less prudent member states to say that all bets are off and that the EU’s fiscal rules should be torn up.

Likewise, European capitals are watching anxiously to see what coalition emerges from the debris. Just as Germans will have to get used to the post-Merkel era, so too, will the rest of Europe.

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Merkel’s ability to guide Europe through crises thanks to her negotiating skills, her consensual approach and her mastery of detail, eased fears of German dominance.

At the same time, her approach raised strong levels of trust in Germany among European electorates (Europeans, for example, have been largely relaxed about a German, Ursula von der Leyen, running the European Commission).

Yet the challenges Europe faces are not just economic. The fall of Afghanistan, the rise of China, the ambivalent signals from the Biden administration about America’s partnership with Europe, all point to a new series of challenges that may not be served by a Merkel-lite successor.

"This is the paradox of Merkel’s legacy," write Piotr Buras and Jana Pugleirin in a paper for the European Council on Foreign Relations (ECFR).

"Germany owes its success mostly to factors that are not sustainable and to circumstances that are now in the past.

"In other words, Berlin’s actions in recent decades have raised expectations about Germany’s potential to be the benevolent leader that a crisis-ridden EU needs so badly, struggling as it is to defend its values and find a place in a world of renewed great power competition.

"To fulfil this role, Berlin will have to reinvent itself. Most importantly, it will need to revise those principles of Merkelism that made Europeans place their hopes on Germany."

The country’s squeamishness when it comes to defence and foreign policy is a case in point, and this relates to the prickly issue of replacing the Tornado jet fighters, which are capable of carrying nuclear weapons.

Biden’s chaotic withdrawal from Afghanistan, and the AUKUS submarine deal with the UK and Australia, have left hard questions for NATO and European defence.

In turn, they will render the construction of a new coalition government difficult, given the radical foreign and defence policies of the Left Party and, to a lesser extent, the Social Democrats and the Greens.

"In both cases — Afghanistan and the AUKUS deal — the lack of US consultation with its allies plays into the hands of the left wing of Germany’s Social Democrats and the Greens," says Judy Dempsey, senior fellow with Carnegie Europe.

"Their pacifist, anti-American sentiments can be quickly tapped into. Both wings of the parties want to rid Germany — even unilaterally — of US nuclear weapons, which are NATO’s security umbrella for Europe."

The Greens will certainly moderate their messaging on foreign policy if the door to power is ajar. Under the leadership of Annalena Baerbock, the party has taken a much more robust and principled stance on human rights and Russia.

By contrast, the Merkel years will be seen as an era when Germany condemned Russia when it suited, but collaborated when German interests were at stake, most acutely in the case of the Nord Stream II pipeline.

Annalena Baerbock, chancellor candidate of the German Greens Party, pictured yesterday

Likewise, if Europe is to forge a more coherent policy and posture on the global stage, due to the waning trustworthiness of the United States, then it will have to think harder about its relationship with China.

Again, Merkel was inclined to give Beijing the benefit of the doubt, not least because of the huge exposure of the German export sector to China.

Indeed, in a European Council on Foreign Relations survey, only 17% of Europeans believe Germany can lead the EU in its relations with China.

In handling the EU’s relations with Russia and the US, only one-fifth and one-quarter of Europeans trust Germany respectively. This will pose an immediate challenge to her successor.

"If the idea of being robust with China meant putting in place very strong [trade] measures, particularly if these affected German industry, that was not something Merkel would do," says Fabien Zuleeg, chief executive of the European Policy Centre (EPC).

"But there was also a more general style point. She believes in dialogue, she believes in trying to work things out, rather than going for confrontation.

"That certainly will change. The next German leader will not have the same style, and will also not have the same audience in China that she has had."

Chinese Premier Li Keqiang and Chancellor of Germany Angela Merkel in Beijing, China in 2019

Taking a more principled stand on China and Russia will also be difficult if the next Chancellor continues Merkel's policy of using kid gloves when democratic values are threatened within Europe itself.

Of all the criticisms that are now levelled against Merkel’s tenure, her tolerance of Hungary’s Viktor Orban, who was in her own European People’s Party (EPP) grouping, is the sharpest.

Next March Hungary will go to the polls, and if the gradual control of state, media and academic institutions by Orban’s Fidesz Party continues, there are real fears that those elections will be neither free nor fair.

The new Chancellor will also have to breathe new life into the Franco-German relationship, historically seen as vital for European integration.

"Europeans have such expectations of the next German government on every major policy issue," says Goran Buldioski, director of the Berlin office of the Open Society Foundations.

"The [new] government cannot fulfil all those expectations, be it on the economy, foreign policy, or migration.

"However, unless Germany quickly shows its mettle on democratic values in its relations with other member states, democracy will fade even more rapidly as the governance system within the EU, not only outside it.

"And that will be the end of the EU’s major comparative advantage over its authoritarian rivals."

The new Chancellor will also have to breathe new life into the Franco-German relationship, historically seen as vital for European integration.

Angela Merkel studiously avoided the "vision thing" when it came to Europe, leaving that field to Emmanuel Macron.

Her departure poses some tricky political questions for the EU, if she is replaced by the SPD’s Olaf Scholz.

The European Commission president Ursula von der Leyen would then be at odds politically with the German government, and it could also upset the delicate balance of senior positions of EU institutions.

Ursula von der Leyen and Angela Merkel at the G20 Compact with Africa meeting in Berlin last August

"You've got that relationship which is essential between the Commission President and the German Chancellor," says one EU diplomat.

"Now they would be from two different parties. What does that mean, for Von der Leyen’s position in particular? And would that push her closer to Paris?"

Dublin, at least, will be reassured that a Chancellor Scholz would continue Germany's instinctive defence of the single market when it comes to the ongoing tensions around the Northern Ireland Protocol.

Speaking to RTÉ News in Cologne on Friday, Scholz was asked what his message to Boris Johnson would be on the Protocol if he were elected Chancellor.

He replied: "The EU is working together with Ireland on all the questions that are important for the country. This was always an activity I supported, also with my colleagues from the member states and finance ministers."

Scholz added: "This will be the political strategy for Europe. We will develop a political strategy that is good for Ireland, for peace."

But Scholz will need time to make his presence felt, given how used Europe has become to having Angela Merkel as the reassuring presence in Berlin.

"I think what Europe will miss is her experience, her network," says Guntram Wolff of the Bruegel think tank.

"Let's not underestimate the power of having been there for 16 years, the power of knowing, not only every head of state and every minister, but probably also having staff who knew everyone for so long.

"That will take time for a new German chancellor to build."