07/27/16 JSTOR Daily
Imagine if the tables were turned, and Mexico was trying desperately to keep American immigrants out.
Picture this: A liberal immigration policy fails to assimilate newcomers. A giant slice of national territory is swamped by foreigners speaking a strange tongue and practicing a different religion. Meanwhile, an influx of desperate newcomers is crossing the Rio Grande seeking a new life.
The government: Mexico. The territory: Texas, transformed by Anglo-American newcomers. And the people crossing the Rio Grande: escaped slaves.
Mexico Institute 