That is the first sentence of their abstract, here is the rest:
To explain this puzzling phenomenon, we develop a theory linking internal migration, localized social institutions (e.g., family and friend networks), and voters’ preferences for social insurance. We start with the observation that social ties provide insurance against adverse life events, such as job loss, and highlight two implications. First, those with strong social networks prefer lower spending on social insurance, because they have access to informal insurance that acts as a substitute for public programs. Second, social ties discourage people from moving, even when better economic opportunities are available in other regions. Combining these mechanisms, we argue that the effect of economic shocks on a region’s politics depends on the strength of social ties. Regions with dense social ties have muted migratory responses to negative shocks relative to regions with weaker ties. Further, those who remain in declining regions are more conservative than those who migrate — resulting in an electorate with lower demand for social insurance. Macro-level analysis of American election results, import shocks, and migration data provide empirical support for the theory’s predictions. An original survey corroborates the micro-level mechanisms. The results have important implications for understanding right-wing populist support in economically declining regions in the U.S. and other post-industrial countries.
That is from a new paper by William Marble and Junghyun Lim.