* Kramp-Karrenbauer took over from Merkel as CDU chief
* She heads to party congress weakened after gaffes
* But CDU does not want damaging leadership race
By Paul Carrel
LEIPZIG, Germany, Nov 21 (Reuters) - Senior members of Germany's ruling party are rallying around their leader, Annegret Kramp-Karrenbauer, before a weekend congress at which she hopes to show she is the right person to succeed Angela Merkel as chancellor.
Kramp-Karrenbauer, who is also defence minister, took over as head of the Christian Democratic Union (CDU) last December after Merkel stepped aside.
But Kramp-Karrenbauer, 57, has made several gaffes since then that have dented her popularity and raised questions about her suitability to be the CDU's candidate for chancellor when Merkel also leaves that job.
On her watch, the CDU also suffered losses in an election to the European Parliament in May and has had mixed success in regional elections.
But a tortuous leadership contest in the Social Democrats (SPD), the junior partner in Merkel's ruling grand coalition, has convinced many Christian Democrats to swing behind Kramp-Karrenbauer, party sources said. This is partly also for lack of a convincing alternative.
"Looking at the SPD, we see the situation they have fallen into and we see that if we remain preoccupied with ourselves, then we won't be crowned with success," a senior CDU official, speaking on condition of anonymity, said before the congress in the city of Leipzig.
The SPD has been leaderless since June when Andrea Nahles quit after its worst result in a European Parliament election. Germany's oldest party is polling at about 15%, only just better than all-time lows.
The CDU's youth wing wants the congress to discuss holding a ballot of members on who should be the conservative bloc's candidate as chancellor at the next federal election, due in 2021, but the party's establishment opposes the initiative.
Meeting under the banner 'Germany's strong middle', the CDU is aiming to reassert itself in the political centre ground, where the Greens have surged, and will debate how to position Germany's social market economy for the digital age.
"Either we change our policy, or people will change the composition of the Bundestag," CDU Saxony state premier Michael Kretschmer told business daily Handelsblatt, adding he was not interested in a party leadership debate.
Another test is looming for Kramp-Karrenbauer over the ambitions of China's Huawei Technologies, which hopes to win 5G network contracts in Germany.
Washington, fearing Huawei's equipment could be used by China for spying, has led a campaign to convince allies to bar it from their 5G networks.
Merkel believes Germany must use security standards as its yardstick when assessing bids to build out its 5G network rather than exclude individual companies. But some CDU members want Huawei excluded.
Trying to force the issue, a group of CDU lawmakers has proposed a congress initiative that would bind the lower house of parliament to decide on the 5G rollout.
"I think there is a lot of support for this initiative," the senior CDU official said.
Kramp-Karrenbauer could find herself at odds with Merkel.
"She looks at this very closely, and is wary of the risks," the official added of Kramp-Karrenbauer. (Editing by Timothy Heritage)