In The Power Elite, American sociologist C. Wright Mills (1916-1962) describes the structure of power in post-World War II society. Mills makes the case that the powerful decision-makers in modern society are members of three separate but interconnected parts: political elites, economic elites, and military elites. Mills argues that American democracy is largely a fairy tale; while different factions within the power elite may have superficial disagreements on certain political issues, in critical moments, the elites will act in concert.
In this vein, Mills is critical of the pluralist model of American society, which argues that power is ultimately owned by the public-at-large. Through voting power and interest groups, the pluralist model argues that the will of the people is always followed. Mills views this as a sugar-coated view of the political process, and notes that this model itself is used by elected politicians to justify any action they decide to take while in office (in other words, because a politician is elected through the voting process, any decision they make can be seen as exercising the people's will).
Mills is part of the sociological tradition of conflict theory, which is rooted in Marxism. Conflict theorists describe society in terms of struggles between social classes; in Marx's case, the struggle between the working class and the bourgeoisie. More contemporary conflict theorists, like C. Wright Mills, have offered more complex descriptions of class structures and divisions.