From 1991 to 1995 he was Senator for urban development and the environment in the city state of Bremen, from 1993 also mayor, and from 1997 to 2017 Co-President of the Heinrich Bцll Foundation, a political Think Tank affiliated with the German Green Party. In 2017 he founded the Center for Liberal Modernity (www.libmod.de) together with his wife Marieluise Beck, a long-term member of the German Bundestag.
