The three contemporary theories of American democracy are hyperpluralism, pluralism, and elite and class theory. Each of these can be applied as a lens to see American politics through.
Pluralism is the theory that different views and opinions give rise to a number of competing parties, such as the Republicans and Democrats. Hyperpluralism is an extension of this, in which there are so many competing interests that it becomes hard for the government to rule. Elite and class theory is the idea that those possessing most of the resources and power are the elite and have a right to govern over those that possess less in society.