Chancellor Angela Merkel's conservative Christian Democrats suffered a setback Sunday when a regional leader was forced to resign over his affair with a 16-year-old girl.
Christian von Boetticher, 40, announced Sunday he was stepping down as chairman of the CDU in Schleswig-Holstein state, in a further blow to Merkel's slumping conservatives.
Boetticher had been the designated successor to CDU state premier Peter Harry Carstensen, 64, who is not running in an election in Germany's northernmost state in May 2012.
Boetticher's relationship with the 16-year-old was not illegal, but triggered complaints in the conservative party.
After a crisis party executive meeting in the state capital in Kiel, CDU officials said he would remain CDU parliamentary floor leader in the state assembly. The CDU rules with the Free Democrats (FDP) in Schleswig-Holstein.
"Christian von Boetticher said that he had misjudged the moral component (of the relationship)," said deputy CDU leader Angelika Volquartz after the crisis meeting.
In a leading national poll published Friday, Merkel's centre-right CDU/CSU and FDP coalition trailed a likely centre-left alliance of Social Democrats and Greens.