Racial threat hypothesis argues that members of the racial majority perceive growing proportions of a minority population as threatening, and in response, take actions to reduce the perceived threat. It has been hypothesized that perceived racial threat may explain the disparate racial demographics of the United States prison population. To test this claim, I utilize census data to establish racial and economic demography changes within U.S. counties between 2000 and 2010, county crime rates, and police expenditure data from the Bureau of Justice Statistics.

By combining these data over the course of ten years, I evaluate the relationship between minority population growth and police expenditures in urban U.S. counties. The findings in this paper provide evidence in favor of the racial threat hypothesis as an explanation of the disproportionate minority prison population by way of increased police spending in areas with minority population growth.