He was German politician and resistance leader in WW II. he started his career as a book binder and became active in catholic trade union activities. he was elected to Reichtag in 1933. After Nazis came to power all trade unions were abolished and were replaced by Nazi controlled labor front. He joined Resistance activities and was arrested by Gestapo but was soon released.. He became close to Cologne resistance circle and the leaders of resistance such as Carl Goender and Claus VON stauffenburg. Who were very active in resistance activities and fearing problems Kaiser went underground for the rest of the war. After the war he again became active in politics. In East Germany and later in west Germany.