"Some Marxists, Communists, Socialists and anarchists, argue that liberal democracy, under capitalist ideology, is constitutively class-based and therefore can never be democratic or participatory. It is referred to as bourgeois democracy because ultimately politicians fight only for the rights of the bourgeoisie. According to Marx, representation of the interests of different classes is proportional to the influence which the economic clout that a particular class can purchase (through bribes, transmission of propaganda, economic blackmail, campaign 'donations', etc.). Thus, the public interest, in so-called liberal democracies, is systematically corrupted by the wealth of those classes rich enough to gain (the appearance of) representation. Because of this, multi-party democracies under capitalist ideology are always distorted and anti-democratic, their operation merely furthering the class interests of the owners of the means of production."
http://en.wikipedia.org/wiki/Liberal_democracy#Dictatorship_of_the_bourgeoisie