In Common Ground for Tea Partiers and Liberals, I suggested economic class distinctions are more important in elections and legislation than are ideologies. I made the point again on Mark Thoma’s blog, The Rightward Shift in the Political Center of Gravity, and Apinak responded with a link to a 2005 paper by Princeton associate professor Martin Gilens, Inequality and Democratic Responsiveness. Here are the abstract and part of the conclusion of the Gilens paper:
Abstract: By allowing voters to choose among candidates with competing policy orientations and by providing incentives for incumbents to shape policy in direction the public desires, elections are thought to provide the foundation that links government policy to the preferences of the governed. In this article I examine the extent to which the preference/policy link is biased toward the preferences of high-income Americans. Using an original data set of almost two thousand survey questions on proposed policy changes between 1981 and 2002, I find a moderately strong relationship between what the public wants and what the government does, albeit with a strong bias toward the status quo. But I also find that when Americans with different income levels differ in their policy preferences, actual policy outcomes strongly reflect the preferences of the most affluent but bear virtually no relationship to the preferences of the poor or middle-income Americans. The vast discrepancy I find in government responsiveness to citizens with different incomes stands in stark contrast to the ideal of political equality that Americans hold dear. Although perfect political equality is an unrealistic goal, representational biases of this magnitude call into question the very democratic character of our society.
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Conclusion
If government policy is uniquely responsive to the preferences of affluent Americans, as the evidence above suggests, by what mechanisms do the affluent exert their influence? My data are not well suited to answering this question, and space constraints preclude even an adequate account of the possible mechanisms at work. But the most obvious source of influence over policy that distinguishes high-income Americans is money and the willingness to donate to parties, candidates, and interest organizations. For example, a study of donations to congressional candidates in 1996 finds that four-fifths of donors who gave $200 or more had incomes in the top 10 percent of all Americans. [Citation omitted.] Since not only the propensity to donate but also the size of donations increase with income level, this figure understates—probably to a very large degree—the extent to which political donations come from the most affluent Americans. . . .
Here is another link to the Gilens paper.