A woman walks north on the beach in Tijuana, Mexico, on Jan. On an August afternoon in , a mysterious man approached the U. For decades, the boundary between the two countries had been little more than an imaginary line in the sand, marked only by the occasional - often crumbling - pillar in the Sonoran desert.
But rampant smuggling, the Mexican Revolution and the outbreak of World War I had split the border town in two, sowing fear and stoking tensions.
As the man walked towards Mexico, where Mexican soldiers were waving him on, a U. Customs inspector suddenly ordered him to halt. So did two American soldiers, one of whom would later say he thought the man was one of the many German spies rumored to be trying to draw Mexico into war with the United States.
Yards away, Mexican officials also shouldered their rifles. When one fired, hitting an American soldier in the face, both sides of the border erupted in gunfire. The two-hour shootout marked the end of an era of easy movement across the boundary in Nogales, she said, as Mexican and American officials quickly agreed to put up a six-foot fence through the middle of the border town.
A Mexican soldier patrols along the U. Long before the perceived threat was Central American asylum seekers, it was German spies and Mexican revolutionaries, prostitutes and polygamists, Chinese immigrants and cattle infected with "Texas fever. It is not just a border but the border, and its enforcement has become a central means by which politicians signal their concern for citizens' safety and security in a hostile world.
