As soon as Friedrich Merz launched his bid to lead Germany’s Christian Democrats, critics said he was an anachronism, a man from the 1990s who wanted to drag the CDU back to its conservative past.

Mr Merz brushes the criticism aside. “There’s nothing retro about me,” he told the Financial Times. “In fact, I would say I’m the most modern of the three candidates, even though I’m the oldest.

“How come? Because all the issues Germany will be facing in the next decade” — an ascendant China, the new great-power rivalry, profound technological change — “I’ve been dealing with them for years,” he said.

It is a bold claim for a man who is still seen by many — even in his own party — as out of step with the times: a millionaire corporate lawyer who defends traditional values and thinks the CDU has drifted too far to the left under his old rival, Angela Merkel.

Many Merkelites think Mr Merz is too abrasive and too rightwing to lead their party. “I’ve nothing against him personally, but I don’t see how he can appeal to, say, workers in eastern Germany,” said one senior CDU MP. “He’s not the right person for our age.”

Mr Merz, 65, is standing in an election that will have far-reaching consequences for Germany’s — and the EU’s — future. Whoever is chosen as the CDU’s new leader on January 16 is likely to succeed Ms Merkel when she steps down this year after 16 years as chancellor.

The contest is effectively a choice between continuity — the Merkel loyalist Armin Laschet, prime minister of North Rhine-Westphalia — and a fresh start under Mr Merz, an unapologetic rightwinger.

The third candidate, Norbert Röttgen, one of the CDU’s leading foreign policy experts, is seen as a long shot, though he has been surging in the polls in recent weeks thanks to a clever, digitally-savvy campaign that has garnered him support among younger CDU members and MPs.

Mr Merz has also been reaching out to the rank-and-file, and his message is simple: that with Ms Merkel’s departure from power this year, Germany has a chance to break out in a new direction.

“For the first time in our postwar history, we will have an election where the incumbent chancellor isn’t running as a candidate,” he said. That holds risks, but also opportunities: the chance to “readjust our policies”. For the first time in years, Germany’s main centre-right party has the chance to overhaul its offer to voters — and “to be a bit freer in the decisions we make”.

Ever since he launched his bid in February, Mr Merz has positioned himself as the man best suited to leading this renewal. The CDU needed to sharpen its profile after the consensual, ideologically fuzzy Merkel years. “We can’t keep saying: let’s have both x and y,” he told the FT. “We can’t keep saying yes and no at the same time.”

The idea is for the party to return to a pro-business economic agenda and a sharper focus on core conservative values. That way, Mr Merz believes, it can win back those who abandoned it “because they couldn’t figure out what [it] actually stands for any more”. Some of those defected to the populist Alternative for Germany; some, he said, no longer vote at all.

But many Christian Democrats do not agree. “The Merkel wing in the CDU says you would win back fewer conservative voters than you would lose by veering away from the centrist Merkel line,” said Andreas Rödder, a historian at Mainz University. “There’s a real conflict there over strategy.”

Mr Laschet is typical of the establishment CDU voices who dismiss Mr Merz’s offer of change. “There are a lot of people who pine for the CDU as it was 20 years ago,” he said. “That’s just going backwards.”

The reference to 20 years ago is pointed. Mr Merz was a leading light in the CDU in the 1990s and early 2000s, carving out a reputation as a pro-market reformer who famously said every citizen should be able to work out their income tax on a beer mat.

But in 2002 Ms Merkel shoved him aside to become leader of the CDU parliamentary group. For a few years Mr Merz sulked from the sidelines, and then in 2009 quit the Bundestag to pursue a career in business, rising to the post of chairman of BlackRock Germany and becoming a millionaire in the process.

Some in the CDU think the motivation for his leadership bid is personal. “It’s late revenge on Merkel, who dropped him like a hot potato,” said one party source.

But Mr Merz dismissed the notion that he had a score to settle with the chancellor as “nonsense”. “Ms Merkel and I had an arrangement, and she didn’t stick to it,” he said. “But that’s OK. It’s 20 years ago. I got over it long ago.”

Mr Merz is leading his rivals in polls of CDU members. Yet they are not an accurate gauge of his chances. The 1,001 delegates who will elect a new leader are cautious functionaries and elected officials: they might find it too risky to back a candidate who is adored by the CDU rank-and-file but could struggle to connect with the type of middle-of-the-road voters who, for the past 16 years, have elected Ms Merkel.

Delegates may also worry about his ability to forge a coalition with the Greens — widely expected to enter government after this year’s Bundestag election. Mr Merz admitted that he was “not [the Greens’] preferred opponent”. “That would be Armin Laschet. He would leave them in peace and let them do their own thing and bring the CDU along,” he said.

Mr Merz’s gaffes may also give the delegates pause. He recently got into trouble for appearing to suggest that some gay people were a danger to children (he blames his political opponents for “aggressively misunderstanding” him). And in an extraordinary outburst in October, he accused “parts of the party establishment” of plotting to thwart his leadership hopes by delaying the election.

“That went down really badly,” said the senior CDU MP. “It’s not the kind of tone the party executive likes.”

Mr Merz is unrepentant. “I’m someone who is not backward at coming forward,” he told the FT. “My view is that sometimes you have to speak plainly. And the problem is that people just aren’t used to that any more.”