In a new paper Ernesto Tiburcio (on the job market) and Kara Ross Camarena study the effect of illegal immigration from Mexico on economic, political and cultural change in the United States. Studying illegal immigration can be difficult because the US doesn’t have great ways of tracking illegal immigrants. Tiburcio and Camerena, however, make excellent use of a high-quality dataset of “consular IDs” from the Mexican government. Consular IDs are identification cards issued by the Mexican government to its citizens living in the United States, regardless of US immigration status. Consular IDs are used especially, however, by illegal immigrants because they can’t easily get US IDs whereas legal migrants have passports, visas, work authorizations and so forth. Tiburcio and Camarena are able to track nearly 8 million migrants over more than a decade.

Our main results point to a conservative response in voting and policy. Recent inflows of unauthorized migrants increase the vote share for the Republican Party in federal elections, reduce local public spending, and shift it away from education towards law-and-order. A mean inflow of migrants (0.4 percent of the county population) boosts the Republican party vote share in midterm House elections by 3.9 percentage points. Our results are larger but qualitatively similar to other scholars’ findings of political reactions to migration inflows in other settings (Dinas et al., 2019; Dustmann et al., 2019; Harmon, 2018; Mayda et al., 2022a). The impacts on public spending are consistent with the Republican agenda. A smaller government and a focus on law-and-order are two of the key tenets of conservatism in the US. A mean inflow of migrants reduces total direct spending (per capita) by 2% and education spending (per child), the largest budget item at the local level, by 3%. The same flow increases relative spending on police and on the administration of justice by 0.23 and 0.15 percentage points, respectively. These impacts on relative spending suggest that the decrease in total expenditure does not simply reflect a reduction in tax revenues but also a conservative change in spending priorities.

The main reason for this, however, appears not to be economic losses such as job losses or wages declines–these are mostly zero or small with some exceptions for highly specific industries such as construction. Rather it’s more about the salience of in and out groups:

We study individuals’ universalist values to capture preferences for redistribution and openness to the out-group. Universalist values imply that one is concerned equally with the welfare of all individuals, whether they are known or not. By contrast, people with more communal values assign a greater weight to the welfare of ingroup members relative to out-group members. We find that counties become less universalist in response to the arrival of new unauthorized migrants. A mean flow of unauthorized migrants shifts counties 0.06 standardized units toward less universalist, i.e., more communal (Panel B, Column 5, std coeff: -0.16). This result is the most direct indication that some of the shift to the political right occurs because migrants trigger anti-out-group bias and preferences for less redistribution. Although this evidence is based on a smaller subset of counties, the impact is large. The change toward more communal values is consistent with theories that hinge on out-group bias. Ethnic heterogeneity breaks down trust, makes coordination more difficult, and reduces people’s interest in universal redistribution (Alesina et al., 1999).

These results are consistent with the larger literature that finds “Across the developed world today, support for welfare, redistribution, and government provision of public goods is inversely correlated with the share of the population that is foreign-born and diverse.” (Nowrasteh and Forreseter 2020). Similarly, one explanation for the smaller US welfare state is that white-black salience reduces people’s interest in universal redistribution.

Contra Milton Friedman, it is possible to have open borders and a significant welfare state but it may be true that the demand for a welfare state declines with immigration, especially when the immigrants are saliently different.