German Student Union
During his study to become a lawyer (and until 1970), Adler was a member of the Socialist German Student Union ("Sozialistische Deutsche Studentenbund") and the Spartacus Marxist Student Group ("Marxistische Studentenbund Spartakus"). Until he left the party in 1989, he belonged to the German Communist Party. In 1990 he became a founding member of the Party of Democratic Socialism (PDS) for Lower Saxony, becoming the long-running state chairperson. For several years, he was a member of the Rules Committee for the PDS, and since 1996, he has belonged to the City Council of Oldenburg, where he is head of the four-member bloc of the Left Party. From February 26, 2008 he served as a member of the Parliament of Lower Saxony, where he was the chairperson and legal spokesperson for his party. Additionally, he is a member of the Associate Committee of the Oldenburg-East Frisian Water Board ("Oldenburgisch-Ostfriesischen Wasserverbandes"), as well as a member of the Associate Committee of the Community Savings Bank ("Sparkassenzweckverbandes").