The CDU wants to use an ultimatum to persuade the former head of the Office for the Protection of the Constitution, Hans-Georg Maassen, to leave the party.
If he doesn't go voluntarily, she threatens an expulsion process.
In the meantime, an arch-conservative group is increasingly coming into focus.
Berlin - From the protection of the constitution to persona non grata: after several verbal gaffes, the CDU presidium unanimously gave former president Hans-Georg Maassen an ultimatum to leave the party.
If he does not leave the CDU by Sunday (February 5) at 12:00 p.m., the party's federal executive should initiate an exclusion procedure "and withdraw his membership rights with immediate effect," the CDU announced on Monday after consultations in the party's presidium.
Maassen had again come under massive criticism in the past few days for statements on Twitter and in an interview.
In a tweet he claimed that the thrust of the "driving forces in the political and media space" was "eliminatory racism against whites".
The historian and head of the Buchenwald Memorial, Jens-Christian Wagner, then accused him of “classic right-wing extremist reversal of guilt” and trivializing the Holocaust.
In an interview, Maassen also spoke of a "red-green racial theory".
Also because of earlier controversial statements, Maassen has been a thorn in the side of some in the CDU for years.
"Again and again he uses the language from the milieu of anti-Semites and conspiracy ideologues to ethnic expressions," says the text now approved by the CDU presidium.
He is constantly violating the principles and order of the party.
"There is no place in our party for his statements and the ideas expressed with them." Maassen had to leave the party.
It was initially unclear whether he would comply with this additional request.
The 60-year-old could not be reached by phone early Monday afternoon, but according to a media report last week he was unimpressed by calls for a party exclusion procedure.
He does not believe that the conditions for this have been met, he said.
Exclusion procedures are considered difficult - in the case of the SPD, for example, several attempts were necessary to throw Thilo Sarrazin out of the party.
And until it succeeded, it still gave the Social Democrats a number of headlines and controversies.
The Thuringian CDU had also asked Maassen to leave the party by board decision.
According to the CDU general secretary there, country chief Mario Voigt spoke to Maassen personally about it last week.
One now wants to wait for Maassen's reaction and then discuss further steps in the state board, the next board meeting is on February 7th.
Maassen is a member of the Thuringian CDU, but has no office or function in the state association.
A spokesman for the state association said that an application for a party exclusion procedure could be made by the state or federal executive board.
A board member can also apply for the procedure.
CDU federal deputy Karin Prien had announced that he would initiate Maassen's party expulsion at the federal executive board meeting on February 13 if he did not leave voluntarily.
The Presidium has now also applied to the Federal Executive Committee to initiate a party exclusion procedure if Maassen does not go voluntarily.
A district party court in Thuringia would decide on the outcome of such a possible procedure in the first instance.
With the criticism of Maassen, a controversial group has again come into focus, which locates itself close to the Union: Maassen was elected chairman of the arch-conservative Union of Values on Sunday with 95 percent of the votes.
This is not an official Union group.
According to its own statements, it has around 4,000 members - not all of them are also members of the CDU or CSU.
The CDU presidium disapproved of the grouping.
"As we understand it, anyone who is a member of the CDU cannot also be a member of the so-called "Union of Values" at the same time," the decision said.
At the latest since Maassen was elected chairman, each of their members had to ask themselves where their political homeland was.
The Union of Values and its ideas are increasingly difficult to reconcile with the values of the CDU.
Maassen's statements are incompatible with the core of the CDU principles.
Members of the Union of Values who are also members of the CDU should leave the Union of Values, it said.
The CDU has an incompatibility decision that is intended to prevent cooperation with the AfD and the left.
According to the CDU, a decision on incompatibility with membership in the Union of Values would have to be decided by a regular party conference.
dpa