Enforcement was further buttressed by the launching of Operation Blockade in El Paso, Texas, in 1993 and Operation Gatekeeper in San Diego, California, in 1994. These operations, led by the U.S. Border Patrol, erected a literal wall of enforcement resources at the two busiest U.S.-Mexico border crossings. They also diverted migratory flows away from these regions, through the Sonoran Desert, and into Arizona. This diversion greatly increased the costs and risks of undocumented border crossing: Since 1986, more than 7,000 migrants have died along the border, and the average cost of crossing has risen from $600 to $4,500, according to estimates from the Mexican Migration Project, which I co-direct.
Although the intent of border enforcement was to discourage migrants from coming to the United States, in practice it backfired, instead discouraging them from returning home to Mexico. Having experienced the risks and having paid the costs of gaining entry, undocumented men increasingly hunkered down and stayed in the United States, rather than circulating back to face the gantlet once more. As a result, the rate of return migration began to fall after 1986 and accelerated with the launching of the border operations in 1993 and 1994.
Because net migration equals the difference between those entering and leaving the United States, the falling rate of return produced a huge increase in the net volume of undocumented migration. Through the 1990s and early 2000s, in other words, the United States spent billions of dollars, only to double the rate of undocumented population growth. Not only that, but Operation Gatekeeper’s diversion of migrants away from California and into Arizona prompted them to continue onward to new destinations throughout the United States. Census data indicate that two-thirds of Mexican migrants who arrived between 1985 and 1990 went to California; by the 1995-to-2000 time period, that share had fallen to just one third, where it has since remained. Led by Mexicans, but also by Central Americans, the fastest-growing Latino populations are now in places like Georgia, North Carolina, and Iowa — not California.
In addition, as male migrants spent more time north of the border, they were increasingly joined by their wives and children. And then they started making babies. At present, almost 80 percent of the 5.1 million children of unauthorized immigrants were born in the United States and are U.S. citizens. In the end, the militarization of the border transformed what had been a circular flow of workers going overwhelmingly to just three states — California, Texas, and Illinois — into a much larger settled population of families living across all 50 U.S. states — not a good outcome for a policy whose goal was the limitation and control of immigration.
Doubling down on a failed policy of border militarization by adding more fences and walls is not only moronic because it would continue, at great cost, a demonstrably counterproductive strategy for restricting immigration — but it is also senseless because net undocumented migration from Mexico has stopped. Trump appears not to have received the memo. By the Department of Homeland Security’s own estimates, the total undocumented population peaked at 12 million in 2008, fell by a million by 2009, and since then has fluctuated around 11 million people.