An estimated 11 million immigrants live and work in the United States illegally. Their fate is one of the big policy questions facing the country. The story of how that population grew so large is a long one that’s mostly about Mexico, and full of unintended consequences.
Prior to the 1920s, the U.S. had few restrictions on immigration, save for a few notable exclusions.
“Basically, people could show up,” says Jeffrey Passel, of the Pew Research Center.
For workers in Mexico, crossing into the U.S. made a lot of economic sense, then and now.
“That person can can make seven, eight, perhaps even 10 times more than they make in Mexico,” says Jorge Castañeda, Mexico’s former foreign minister.
As more people came into the U.S. to find work, Mexicans became a larger percentage of the workforce.
“Mexican immigration is something from our grandparents’ era,” says Michael Clemens, an economist at the Center for Global Development. “The fraction of the labor force in Kansas that was Mexican in 1929 was higher than it was in 1990. The same is true of Arizona. The same is true of New Mexico.”