He sat in the Reichstag as a National Liberal from 1872 to 1878, and again in 1881 and 1882, and from 1889 onwards he represented the University of Berlin in the Prussian Upper House.
The two great works by which Hinschius established his fame are the Decretales Pseudo-Isidorianae et capitula Angilrantni (2 parts, Leipzig, 1863) and Das Kirchenrecht der Katholiken and Protestanten in Deutschland, vols.
The first of these, for which during 1860 and 1861 he had gathered materials in Italy, Spain, France, England, Scotland, Ireland, the Netherlands and Belgium, was the first critical edition of the False Decretals.
The six volumes actually published (System des katholischen Kirchenrechts) cover only book i. of the work as planned; they are devoted to an exhaustive historical and analytical study of the Roman Catholic hierarchy and its government of the church.
The work is planned with special reference to Germany; but in fact its scheme embraces the whole of the Roman Catholic organization in its principles and practice.
Epoch-making in its application of the modern historical method to the study of ecclesiastical law in its theory and practice, it has become the model for the younger school of canonists.