By Paul Carrel and Andreas Rinke
BERLIN (Reuters) - Annegret Kramp-Karrenbauer's path to succeed Angela Merkel as Germany's chancellor seemed clear when she replaced her as leader of the governing Christian Democrats (CDU) last December.
Ten months later, members of her own party are debating whether AKK, as she is widely known, is the right person to lead the European Union's most powerful country and biggest economy.
After a number of public gaffes, including poking fun at trans-gender people in a light-hearted carnival speech, her ratings have slumped. On her watch, the CDU suffered losses in an election to the European Parliament in May and has had mixed success in regional elections.
Senior CDU leaders say Kramp-Karrenbauer still has time to prove herself. She and Merkel say the chancellor will complete her term, which ends in 2021, giving the CDU more than a year to agree on a candidate.
But with doubts growing about AKK's suitability to be chancellor, a senior CDU politician told Reuters: "The chancellor question has not been settled."
The stakes are high. A messy transition of power would risk destabilizing Germany after a decade of economic expansion under Merkel, who for years has been the EU's most influential head of government, helping guide the bloc through multiple crises.
Further political uncertainty in Germany, the EU's most important source of funding, would be a big concern for many other EU member states seeking unity and reliable, predictable allies as a time when its future could be undermined by Britain's departure.
POLE POSITION
Kramp-Karrenbauer, 57, is still in pole position to become the CDU candidate for chancellor as the role is traditionally handed to the party chief.
A former state premier in Saarland in western Germany, she won the party leadership on Dec. 7 last year. A Merkel protege, she was seen by senior party figures as having appeal right across the CDU, and since July has also been defense minister.
But the CDU's youth wing and a sister party which is part of Merkel's coalition government have expressed their reservations about her and now say they want a ballot of members on who should be the conservative bloc's next candidate as chancellor.
The CDU could discuss whether to hold such at its annual congress next month.
Even Kramp-Karrenbauer's close supporters have privately told Reuters she is suffering a loss of confidence after a baptism of fire as party chair.
She was widely criticized in March for mocking "latte macchiato" leftists in Berlin who want gender-neutral toilets, and was ridiculed in February for addressing a high-profile CDU meeting as Social Democrats.
Kramp-Karrenbauer surprised viewers by suggesting to a TV chat show host that she may have to back a better candidate for the chancellorship, and faced criticism after she called for rules about expressing online opinions before elections in response to a YouTube video critical of the CDU.
"We all make mistakes, that's not the problem. She made a few avoidable mistakes," said a senior CDU official who spoke on condition of anonymity because of the sensitivity of the matter.
The official said he still supported her but added: "In the first weeks (in office), Germans have a look at someone and make up their mind: 'Do we trust her, do we like her or not?' Once they've made up their minds, it's very difficult."
An opinion poll for Spiegel magazine this month found Kramp-Karrenbauer had only half as much support as last December and that only 29% of German voters now wanted her to have a more important role. A poll published by Bild on Oct. 5 showed about 63% of voters felt she was unsuited for the job of chancellor and only 11% were in favor of her having the post.
POTENTIAL RIVALS
Her chief rival for the party leadership last year, veteran politician Friedrich Merz, is circling. He has been telephoning around the party to gauge his support, one party source said.
After referring to "mistakes" made by Kramp-Karrenbauer, he told the conservatives' youth wing at the weekend: "I can understand that there will be discussion about how things proceed, about how further personnel decisions should perhaps be made ... If you want me on board, then I'm on board!"
Bild has listed Merz, Health Minister Jens Spahn and CSU leader Markus Soeder as possible conservative candidates to be chancellor. Armin Laschet, the premier of North Rhine-Westphalia state, was another potential candidate mentioned to Reuters by several CDU sources.
Kramp-Karrenbauer might benefit if Merkel did not see out her term as chancellor because her rivals would have less time to prepare for an election, but she has denied asking her to step down early.
AKK may also benefit if the Social Democrats (SPD) pull out of the coalition government after a mid-term review of the arrangement later this year, forcing a new election and possibly hastening the end of Merkel's tenure as chancellor.
"The longer Merkel remains chancellor, the more her {Kramp-Karrenbauer's) prospects will fade," a senior CDU official said.