The San Diego–Tijuana region is one of the most perplexing places in the Americas

Dr. Portillo, a Mexican physician, lives with her husband and son in a balcony-festooned six-bedroom house in a gated suburb. The adobe walls that enclose the garden, the coloured tiles embedded in the walls and the servants’ garden house are all typical of the home of a prosperous Mexican family. The multi-generational collection of relatives who occupy the spare bedrooms also reflect Mexican tradition. Dr. Portillo receives her patients in an office located in a tower in the northern Mexican city of Tijuana; since many of the patients are American, much of her working day takes place in English. When she goes home at night, she relaxes by speaking to her husband and son in Spanish. Her son, however, often responds in English because Dr. Portillo’s typical Mexican home is located in suburban California.

Dr. Portillo’s husband is an American, born in the southwestern United States into a family that immigrated from Mexico two generations ago. Until he met his wife, then a young medical school graduate newly arrived in California, Spanish was a language of which he had only a passive understanding. As a result of his marriage, he has recovered his fluency. While Dr. Portillo’s son, who was spoken to in Spanish as an infant, is drawn toward English, her husband, who grew up speaking English, has moved in the direction of Spanish. Dr. Portillo, who discovered after immigrating that she would not be allowed to practise medicine in the United States, has achieved her American dream home, built in a distinctively Mexican style, by treating American patients, who pay her in U.S. dollars, in Mexico.

Contradictions such as these make the San Diego-Tijuana region one of the most perplexing places in the Americas. The international boundary line at the heart of these two cities, which are creeping toward each other across low brown hills, is a blemish on the landscape, at first glance an insurmountable barrier; yet by establishing different ground rules on either side of the line, the border inspires the creative evolution of forms of life that could not exist either in a purely American or a purely Mexican context. The region is evolving toward a complex integrated culture that belongs to neither Mexico nor the United States. In spite of this, U.S. politicians continue to win votes by promising to keep immigrants out. The U.S.-Mexican border is an ugly, depressing place where, each year for the past ten years, between 37 and 4 people have died trying to enter the United States without documents. The old head-high red metal fence is rusting. Separated by an arid no man’s land from this relic stands The Wall: the blank concrete barricade, as tall as a three-storey building, that the United States threatens to extend along the length of its border with Mexico.

This Berlin Wall for the twenty-first century reflects the ironic era of its construction. Built to protect a territory defined in terms of culture rather than ideology, it is breached thousands of times a day by cleaning ladies and manual labourers who turn its meaning on its head. Indeed, the United States government encourages certain categories of people to ignore the border. In this, as in other areas, the economics of globalization heightens social stratification. Mexicans who live close to the border can receive a visa that authorizes them to work in U.S. border towns but forbids them from penetrating deeper into the U.S. or residing there. Many Mexicans take advantage of this system to travel at dawn every day to San Diego, where they clean houses or work in gardens. Unlike millions of other poor Mexicans—those who risk their lives trying to cross The Wall—these workers earn cash dollars and pay taxes to neither the U.S. nor Mexico. Professionals like Dr. Portillo, who do pay taxes, can apply for a SENTRI (Secure Electronic Network for Travellers’ Rapid Inspection) pass for their car windshields. This allows them to take the express lane at the border, sweeping past the two-hour lineup of cars waiting to reach U.S. Immigration, with no questions asked.

As the case of Dr. Portillo illustrates, many of the Mexicans moving to the United States are not poor. The most dramatic impact of NAFTA in Mexico has been to debilitate the powerful middle class, which, through most of the twentieth century, gave the country a political stability enjoyed by no other Latin American nation except Costa Rica. Now, as educated Mexicans emigrate in order to salvage their middle-class status, California is awash in Mexican engineers, medical professionals, teachers, computer programmers and graphic designers. Many of the people parking SUVS in the shopping malls of San Diego are ethnically Mexican, identify themselves as American and speak both languages. On the southbound trip, entering Mexico from the United States, there is no border control unless one is unfortunate enough to receive a rare red light at the immigration post. Americans drive into Tijuana with no questions asked, warned only by a sign informing them ungrammatically that “Guns Illegal in Mexico.” Mexico’s aversion to private citizens packing private armour may be the sole cultural difference between San Diego and Tijuana that is destined to survive.

South of Tijuana, condominium towers cling to the cliffs of the rough coastline. A view of the Pacific costs less here than it does in pricey southern California, and the signs advertising the condos, like those in the nearby shops, are in English. The only words in Spanish are sin enganche—“no downpayment required”—a phrase that is excluded from the English versions and that lets Mexicans know that they, too, can aspire to own condos in Mexico. In an oceanfront restaurant fifty kilometres down the coast, everyone is speaking Spanish, yet no one blinks at the English-only menu. In the adjacent market Anglo-Californians speak halting Spanish with Mexican women who have woven the logos of the Los Angeles Dodgers and the San Francisco 49ers into traditional ponchos. On my return trip to San Diego, I cross the border on foot to avoid the backed-up traffic. The border guard asks me for my visa, unaware that Canadians don’t need visas to enter the U.S. The only country he deals with, he says apologetically, is Mexico. In the darkness outside, cars in the express lanes hum past the two-hour traffic jam. It is a statistical certainty that during the night a Mexican without documents will die trying to cross the border. Along this selective frontier, two cultures are merging in a way that consolidates the social stratification common to both. Cultures may blend as globalization proceeds, but the poor and the rich will continue to make separate crossings.