We study the political impacts of unauthorized Mexican migration to the United States. Our
identification strategy relies on two shift-share instruments that combine variation in
migration inflows and migrant networks using data on more than 7 million likely
unauthorized migrants who obtained consular IDs. We identify evidence of conservative
electoral and policy responses at the level of a US county. Unauthorized migration
significantly increases the vote share of the Republican Party in federal elections and …

We study the political impacts of unauthorized Mexican migration to the United States. Our
identification strategy relies on exogenous variation in Mexican municipalities and migrant
networks from data on over 7 million likely unauthorized migrants who obtained consular
IDs. We find evidence of conservative electoral and policy responses. Unauthorized
migration significantly increases the vote share of the Republican Party in federal elections,
decreases spending on education, and increases relative spending on policing and on the …