Princeton, N.J.
THE Mexican-American border is not now and never has been out of control. The rate of undocumented migration, adjusted for population growth, to the United States has not increased in 20 years. That is, from 1980 to 2004 the annual likelihood that a Mexican will make his first illegal trip to the United States has remained at about 1 in 100.
What has changed are the locations and visibility of border crossings. And that shift, more than anything, has given the public undue fears about waves of Mexican workers trying to flood into America.
Until the 1990's, the vast majority of undocumented Mexicans entered through either El Paso or San Diego. El Paso has around 700,000 residents and is 78 percent Hispanic, whereas San Diego County has three million residents and is 27 percent Hispanic. Thus the daily passage of even thousands of Mexicans through these metropolitan areas was not very visible or disruptive.
This all changed in 1992 when the Border Patrol built a steel fence south of San Diego from the Pacific Ocean to the port of entry at San Ysidro, Calif., where Interstate 5 crosses into Mexico. This fence, and the stationing of officers and equipment behind it, blocked one of the busiest illicit crossing routes and channeled migrants toward the San Ysidro entry station, where their numbers rapidly built up to impossible levels.
Every day the same episode unfolded: the crowd swelled to a critical threshold, whereupon many migrants made what the local press called "banzai runs" into the United States, darting through traffic on the Interstate and clambering over cars.
Waiting nearby were Border Patrol officers, there not to arrest the migrants but to capture the mayhem on video, which was later edited into an agency documentary. Although nothing had changed except the site of border crossings, the video gave the impression that the border was overwhelmed by a rising tide of undocumented migrants.
In response to the ensuing public uproar, the policy of tougher border enforcement was expanded to all of the San Diego and El Paso area in 1993 and 1994. So migrants began going to more remote locations along the border in Arizona. In 1989, two thirds of undocumented migrants came in through El Paso or San Diego; but by 2004 two-thirds crossed somewhere else. (My statistics on Mexican immigration come from a study I have been undertaking with financing from the National Institutes of Health since 1982.)
Unlike the old crossing sites, these new locations were sparsely settled, so the sudden appearance of thousands of Mexicans attracted considerable attention and understandably generated much agitation locally. Perceptions of a breakdown at the border were heightened by news reports of rising deaths among migrants; by redirecting flows into harsh, remote terrain the United States tripled the death rate during border crossing.
Less well known is that American policies also reduced the rate of apprehension, because those remote sectors of the border had fewer Border Patrol officers. My research found that during the 1980's, the probability that an undocumented migrant would be apprehended while crossing stood at around 33 percent; by 2000 it was at 10 percent, despite increases in federal spending on border enforcement.
Naturally, public perceptions of chaos on the border prompted more calls for enforcement and the hardening strategy was extended to other sectors. The number of Border Patrol officers increased from around 2,500 in the early 1980's to around 12,000 today, and the agency's annual budget rose to $1.6 billion from $200 million. The boundary between Mexico and the United States has become perhaps the most militarized frontier between two nations at peace anywhere in the world.
Although border militarization had little effect on the probability of Mexicans migrating illegally, it did reduce the likelihood that they would return to their homeland. America's tougher line roughly tripled the average cost of getting across the border illegally; thus Mexicans who had run the gantlet at the border were more likely to hunker down and stay in the United States. My study has shown that in the early 1980's, about half of all undocumented Mexicans returned home within 12 months of entry, but by 2000 the rate of return migration stood at just 25 percent.
The United States is now locked into a perverse cycle whereby additional border enforcement further decreases the rate of return migration, which accelerates undocumented population growth, which brings calls for harsher enforcement.
The only thing we have to show for two decades of border militarization is a larger undocumented population than we would otherwise have, a rising number of Mexicans dying while trying to cross, and a growing burden on taxpayers for enforcement that is counterproductive.
We need an immigration policy that seeks to manage the cross-border flows of people that are inevitable in a global economy, not to repress them through unilateral police actions.