The purpose of democracy - supplanting old belief in the necessary absoluteness of establish'd dynastic rulership, temporal, ecclesiastical, and scholastic, as furnishing the only security against chaos, crime, and ignorance - is, through many transmigrations, and amid endless ridicules, arguments, and ostensible failures
Public opinion is presumptively an input to policy formation in a democracy because politicians respond to it or at least are believed to respond [to it].
Where some people are very wealthy and others have nothing, the result will be either extreme democracy or absolute oligarchy, or despotism will come from either of those excesses.