Peter Andreas' post at Bloomberg's Echoes blog describes one interesting episode in cross-border North American migration: a century ago, Chinese migrants entered the United States in large numbers via Mexico.
As political pressure to “do something” about the “yellow peril” intensified, Congress first passed the Page Act of 1875 (with enforcement mostly aimed at keeping out Chinese prostitutes), followed by the far more sweeping Chinese Exclusion Act of 1882. These laws -- the federal government’s first attempts to keep out “undesirables” -- were renewed, revised, strengthened and extended to other Asian groups in subsequent years and decades (and weren’t repealed until 1943).
As front-door entry through San Francisco and other U.S. seaports became more difficult in the late 19th century, increasing numbers of Chinese immigrants turned to the back entrance: the vast and minimally policed northern and southern U.S. land borders.
In the late 1880s and ’90s, Canada was a favored base for smuggling immigrants into the U.S. But as Canadians began cooperating with American authorities, Chinese migrants and their smugglers increasingly turned to Mexico. That country was far less inclined to cooperate with the U.S. because of the still-festering wounds of the Mexican-American War about half a century earlier.
[. . .]
The Treaty of Amity and Commerce signed by China and Mexico in 1899, and the establishment of direct steamship travel between Hong Kong and Mexico in 1902, opened the door for a surge in Chinese migration. And this, in turn, provided a steppingstone for clandestine migration to the U.S. In 1900, there were just a few thousand Chinese in Mexico; less than a decade later, almost 60,000 Chinese migrants had departed for Mexico. Some stayed, but the U.S. was a far more attractive destination. In 1907, a U.S. government investigator observed that as many as 50 Chinese arrived daily by train in the border town of Juarez, yet the Chinese community in the town never grew.
Foreshadowing future debates, a January 1904 editorial in the El Paso Herald-Post warned that “if this Chinese immigration to Mexico continues it will be necessary to run a barb wire fence along our side of the Rio Grande.”