The principle of government do the people have the duty described in this quote is under social contract. It is an implicit agreement among the members of a society to cooperate for social benefits, for example by sacrificing some individual freedom for state protection. Theories of a social contract became popular in the 16th, 17th, and 18th centuries among theorists such as Thomas Hobbes, John Locke, and Jean-Jacques Rousseau, as a means of explaining the origin of government and the obligations of subjects.