The goal of the analysis is to identify which of the two channels (i.e., increases in black housing demand and/or reductions in white vigilante activity) actually drove demand for passage of municipal segregation ordinances. Although our data and estimating strategies are limited, the patterns we observe are consistent with the predictions of the model, though the evidence for the vigilante channel is stronger than for the housing demand channel. In particular, whether we use city-level or ward-level data, we find only mixed evidence that demand for segregation ordinances is strongest in areas with the fastest growing black populations.
By contrast, we find relatively strong and robust evidence for the second channel involving white vigilante activity. Across a variety of model specifications and different measures of white vigilante activity, it is clear that in the cities where whites were able to police color lines and punish deviations through private channels, there was relatively little demand for segregation ordinances. For example, the data show that in cities located in counties with high lynching rates (a direct indicator of the ability of whites to organize privately to punish blacks for violating established racial norms) the probability of passing a segregation ordinance is significantly lower than in places with low lynching rates. Similarly, cities that possessed a robust volunteer fire department (an alternative measure of the ability to provide public goods through private channels) are significant less likely to pass a segregation ordinance. We supplement our city-level analysis with ward level data from St. Louis. With the ward-level data from St. Louis, we can identity which wards were the strongest supporters of the city’s segregation ordinance. The patterns observed in St. Louis suggest that support for the city’s segregation ordinance was strongest in the wards where it was difficult for white communities to coordinate private vigilante activity (pg. 4-5).
The authors conclude,
The existing literature on the origins of municipal segregation ordinances argues that segregation ordinances were passed largely because of rapidly growing black populations in urban areas and variation in the intensity anti-black preferences across cities. Our results suggest the existing literature needs to be revised. While there is evidence that growing black populations might have played a role in the propagation of segregation ordinances, the results here suggest that a decline in the ability of whites to provide a local public good (i.e. segregation) through private vigilante activity was especially important. In particular, the negative coefficient on lynching and the positive coefficients on white population growth are consistent with the hypothesis that segregation ordinances were passed in those cities where it was becoming increasingly difficult for whites to organize and punish blacks for violating established color lines in residential housing markets.
More generally, the model developed and tested here has broad implications for our understanding of residential segregation the processes that give rise to it. Of particular interest is the exploration of how market processes such as tipping interact with institutional change. While prior research has tended to treat market-related processes such as tipping independently from institutions, both formal and informal, the framework here integrates them. In the process, it can help us understand political institutions and market processes work together to drive segregation and make it persistent (pg. 34-35).