* 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
* Party officials agree compromise on 5G rollout and Huawei (Adds compromise on Huawei)
By Paul Carrel and Andreas Rinke
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 Democratic party (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 resigned after the centre-left party's worst result in a European Parliament election. The SPD, 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 (lower house of parliament)," CDU Saxony state premier Michael Kretschmer told business daily Handelsblatt, adding he was not interested in a party leadership debate.
Ahead of the party congress on Friday and Saturday, Merkel agreed to go along with a compromise proposal on the rollout of Germany's 5G network, seeking to head off a row between the government and members of her own party that could have put Kramp-Karrenbauer in an awkward position.
Some CDU lawmakers want China's Huawei, which the United States fears could be used by Beijing for spying, to be excluded from 5G contracts. Merkel wants security standards to be the yardstick, rather than singling out any one company.
The compromise calls for firms that bid for 5G contracts to meet tight security guidelines guarding against foreign state influence, and for the Bundestag to be involved in the decision making. The proposal does not single out Huawei.
"The chancellor can go along with this initiative because it refers to the decisive criteria," her chief of staff, Helge Braun, told Reuters. "There is no exclusion of a company per se."
But Merkel promised CDU officials that Germany will use more European components in the rollout of its 5G network than is the case in the existing infrastructure, top party officials said, with Ericsson's and Nokia's set to gain. (Editing by Timothy Heritage and Mark Heinrich)