(CNN) Angela Merkel's grand transition plan has derailed after her handpicked successor, Annegret Kramp-Karrenbauer, unexpectedly called it quits on Monday.
Kramp-Karrenbauer, better known as AKK, announced she would not stand as the Christian Democratic Union's (CDU) candidate to be German chancellor in the next federal election. She is also stepping down as the party's chairwoman, according to the CDU's press office.
Merkel, who has been chancellor for almost 15 years, said in 2018 that she would not run again when her term expires in 2021. At that time, she stepped down as party leader and endorsed Kramp-Karrenbauer as her successor. But her attempt at securing an orderly transition of power -- as well as her own legacy -- appears to have failed.
Some say the chaos is of Merkel's own making.
"To me, this failure is symptomatic of the way Angela Merkel has exercised power," said Henrik Enderlein, president of the Hertie School of Governance in Berlin. "She never allowed anyone to rise within the federal government and become a natural heir."
Enderlein pointed out that after Merkel stepped down as CDU leader in 2018, the top three candidates for the post were Friedrich Merz, who had spent years outside of politics, and two rather junior politicians -- 38-year old health minister Jens Spahn and Kramp-Karrenbauer.
"AKK was a still relatively inexperienced regional governor of a tiny German state," Enderlein said.
Florian Hense, an analyst at Berenberg Bank, said that despite the chaos, it seemed extremely unlikely that Merkel would change her mind and run again in 2021.
He said Merz and Armin Laschet, the prime minister of North Rhine-Westphalia, are likely to be the top contenders in the next leadership race.
Merz lost narrowly to AKK in 2018, and Hense said he might be better suited to take on the far-right Alternative for Germany than the other leadership candidates. He would certainly be a popular choice for those who are looking for a bigger change when Merkel's reign comes to an end.
Merkel formed a grand coalition with the center-left Social Democrats (SPD), and some parts of the CDU have criticized her for what they see as a move to the left. Merz, a corporate lawyer who has spent the past decade working for the investment company BlackRock, would move the party more to the right.
Spahn is also likely to throw his hat into the ring, although Hesse said his chances are likely to be limited, since he is not as popular among the wider German population.
Whoever becomes the next leader of the CDU will face the challenge of reuniting a deeply divided party.
That division was on display last week, when a regional branch of the CDU in the eastern German state of Thuringia breached a decades-old taboo and teamed up with the AfD to elect a liberal candidate as the state's prime minister.
"Thuringia is an example of how the right wing of the CDU wants to take decisions autonomously and implicitly cooperate with the far-right AfD," Enderlein said.
AKK's failure to force the regional CDU in Thuringia to stick to the official party line was just the last in a long list of moves that made her leadership look weak.
Speaking at a news conference on Monday, she said the decision to resign had been growing in her mind for some time. She called on the party to become "stronger than today."
AKK's shock announcement has thrown the CDU -- and the whole of Germany -- into political uncertainty.
One likely consequence of that will be a greater focus on domestic issues among German political leaders, something which could spell bad news for the European Union, which is desperately looking for strong leadership as it recovers from the United Kingdom's exit from the bloc.
Enderlein said the episode shows that Merkel is still the cornerstone of German politics. The four-time chancellor is on her way out -- and she certainly doesn't want her legacy to be associated with chaos. But Enderlein warned that might be exactly what's on the cards.
"Her departure ... will leave a big void [and] is likely to fundamentally deeply destabilize the German political system," he said.