In his "Vrije Politieke Stellingen" (1665- 'some Free Political Theses'), Van den Enden advocates for freedom of speech and the general right to develop. He further develops the idea of popular sovereignty. He is convinced that the people, by the practice of democracy in popular assemblies and concertations, will gain experience and insight. As an example of democratic functioning, he gives the method of such working as used in Holland during the Eighty Years' War against Spain. But he also warns that all officers must be followed with a watchful eye, especially those who excel in eloquence and greed.