Income Inequality and Ideological Positions in the U.S. Congress

Abstract

Over the past twenty years, there has been much discussion about two of the most important recent trends in American politics: the increase in income inequality in the United States and the increase in ideological and partisan polarization, particularly in the U.S. House. These two national-level trends are commonly thought to be positively related. But, there are few tested theoretical connections between them, and it is potentially problematic to infer individual-level behavior from these aggregate-level trends. In fact, an examination of the literature reveals, at least, three different theoretical outcomes for district-level income inequality on voter and congressional ideological positions. I explore these district-level theoretical and empirical possibilities as well as test them over decades with three different measures of income inequality. I argue and demonstrate that higher district levels of income inequality are related to higher levels of ideological liberalism in the U.S. House. This stands in contrast to the national-level trends, but it tracks closely to traditional understandings of congressional behavior.