October 30, 2026
The violence created by Mexico’s war on drugs in the late 2000s did more than reshape communities south of the border. It also produced an unexpected economic ripple effect in the United States: According to a recent study, Mexican migration driven by the violence, largely involving undocumented immigrants, increased employment among U.S.-born workers.
The study, by Mark Borgschulte, Yuci Chen, and Eduardo Medina-Cortina, examines the aftermath of President Felipe Calderón’s 2006 election and his decision to intensify the Mexican government’s campaign against powerful drug cartels. The crackdown destabilized the cartels and triggered a brutal struggle over territory. Annual homicides in Mexico rose from roughly 10,000 to 25,000 between 2007 and 2012, driving tens of thousands of people from their homes. Many headed north, most without legal immigration status.
Tracking these migrants is difficult because undocumented immigrants are often poorly represented in official surveys. The researchers therefore turn to a different source of data: identification cards issued by Mexican consulates in the United States. Applications record both a migrant’s Mexican municipality of origin and the U.S. county where he or she lives. The researchers compared Mexican municipalities where candidates from President Calderón’s party narrowly won mayoral elections with those where they narrowly lost. Narrow victories led to greater drug-war violence and migration. Historical migration networks then identified which U.S. counties were most exposed to these movements, allowing the researchers to distinguish their effects from ordinary migration patterns.
The results challenge a familiar assumption about immigration: that an influx of foreign workers necessarily leaves U.S.-born workers with fewer jobs or lower wages. Instead, counties receiving more migrants experienced higher employment and lower unemployment among U.S.-born residents, particularly those without college degrees. In the medium run, roughly five years after the elections, the estimates imply about one additional U.S.-born worker employed for each additional undocumented Mexican resident in the receiving counties. These population increases reflected both new arrivals and longer stays by existing migrants. The employment gains emerged during and after the Great Recession, when many U.S. labor markets had substantial unemployment. They faded over roughly a decade, even though the receiving counties continued to have larger Mexican immigrant populations.
The findings support an explanation that immigration debates often overlook: migrants are consumers as well as workers. They need housing, food, and local services. That additional demand can encourage businesses to expand and hire more workers. Employment gains were concentrated in sectors serving local customers, consistent with increased demand for goods and services. Differences in skills and access to jobs may also have contributed to the employment response.
Notably, the researchers find no evidence that U.S.-born workers experienced wage losses, even in industries such as construction, restaurants, and building services where undocumented immigrants were concentrated. Language barriers and legal restrictions may limit direct competition for the same jobs.
An important element of context is that migrants arrived during the Great Recession. Thus, the study shows how local labor markets adjusted to an unexpected increase in their immigrant populations during a period of economic weakness. The resulting employment gains for U.S.-born workers were substantial in the medium run but diminished as local economies adjusted, without evidence of lower wages for U.S.-born workers in either the medium or long run.
Experts
