There is some research that has explored a potential link between an increase in foreign-born population in American local communities and a shift toward political conservatism, though the findings are complex and mixed.
One of America’s most respected social scientists, Robert Putnam, at Harvard’s Kennedy School of Government, has studied the social impact of ethnic diversity. The results shocked him so much that he withheld reporting them for years. Fighting his personal pro-immigrant leanings, he concluded, “immigration and ethnic diversity challenge social solidarity and inhibit social capital.”
He describes social capital as a collective capacity to spark civic participation and trust, keys to building democracy. In his 2006 lecture, “E Pluribus Unum,” Putnam warned “The more ethnically diverse a residential context is, the less we trust…” The more racially diverse a community, the less trust exists between neighbors. Even trust within groups is lower in more diverse settings.
Here is a fresh study which looked the local responses which the authors associate with the rise in the number of unauthorized immigrants.
“In response to newcomer unauthorized migrants, county vote share for the Republican party increased in House and presidential elections. Local government agencies reduced total expenditure, divested in education, and increased relative spending in policing and the administration of justice. Migration creates formal job loss in the construction and hospitality and leisure sectors as jobs moved to the informal sector. The arrival of newcomers caused an increase in the number of poor people. Established residents, display more outgroup bias. Newcomers generate population loss, especially among white residents.”
Here is the article, published November 2023