From the peer-reviewed Princeton study of 1,779 policy outcomes from 1981 to 2002, which concluded: "economic elites and organized groups representing business interests have substantial independent impacts on U.S. government policy, while average citizens and mass-based interest groups have little or no iependent influence."
Link to Study:
Testing Theories of American Politics: Elites, Interest Groups, and Average Citizens by Princeton University Prof Martin Gilens and Northwestern University Prof Benjamin I
Reviews:
The US is not a democracy but an oligarchy, study concludes, by JC Sevcik, UPI