Career
But in 1962 he left the party organisation for the Frankfurter Rundschau, a leading newspaper then considered liberal. From 1971 on he worked again for the Freie Demokratische Partei (Free Democratic Party), this time as secretary-general of chairman Walter Scheel. Being elected to the Bundestag in 1972 he became vice chairman of the Bundestag party.
Flach died at the age of 44 in 1973 after having suffered a stroke a month before.
He was one of the authors of the left liberal Freiburger Thesen, a programmatic paper the party accepted at its congress in October 1971. They stand for the turn to the left the party started in 1968 to become more independent from the conservatives and have a coalition with the social democrats (1969-1982).
He has been honoured with several prizes for his work as a journalist.