His habilitation (higher academic qualification), also from Munich, and supervised by Karl Engisch, would follow in 1961.
[2] Despite attempts by Munich and other university level institutions outside Bavaria to lure him away, he remained at Erlangen for more than fifty years.
[2] His academic research is centred on constitutional law, theory of the state, along with legal philosophy and method.
In terms of theory of the state, his themes include the legitimation and cultivation of democracy, especially regarding the rule of law, and the oligarchic components of pluralistic democracy, furthermore the federalism (the limitation of authorities, the functioning and the democratic ambiguity of federalism) and the problems of the bureaucracy.
James R. Maxeiner (translated Reinhard Zippelius (son of Reinhold)) Thinking like a lawyer abroad: putting justice into legal reasoning, Washington University Global Studies Law Review Vol 11/1, January 2012