In a collection of brilliant essays ranging over a number of disciplines, Hume reflects on the key aspect of the state - why people obey:
Nothing appears more surprizing to those, who consider human affairs with a philosophical eye, than the easiness with which the many are governed by the few; and the implicit submission, with which men resign their own sentiments and passions to those of their rulers. When we enquire by what means this wonder is effected, we shall find, that, as Force is always on the side of the governed, the governors have nothing to support them but opinion. It is therefore, on opinion only that government is founded; and this maxim extends to the most despotic and most military governments, as well as to the most free and most popular. The soldan of Egypt, or the emperor of Rome, might drive his harmless subjects, like brute beasts, against their sentiments and inclination: But he must, at least, have led his mamalukes, or prætorian bands, like men, by their opinion.
About this Quotation:
If Edmund Burke pondered over one of the key questions of political theory, “who quards us from the guardians?”, David Hume was pondering an equally difficult problem: “why is it so easy for the few in power to govern the many?” His answer was that “opinion”, or the beliefs the many hold about the legitimacy of those who rule, keeps the many from throwing off their rulers. This means that minimal force is required by the rulers to keep the many in line.