How and why did the desert border become a sharp dividing line at certain times but not others?

The border between the U.S. and Mexico has, at times, been a sharp dividing line and yet not so much during other times, leaving the question as to why. St. John discusses and analyzes various trends and historical moments that brought sharp attention to the border that divided the two countries, which I will discuss in this blog.

The border between the U. S. and Mexico was, at times, just a line on a map that had little meaning to the inhabitants residing within that territory. Initially both the U.S. and Mexico sought to define the line for sovereignty reasons, to establish control and laws over its people as well as fend off those who sought to create new nations in what was Mexican Territory, especially the Apache. The Apache did not acknowledge Mexican or U.S. territory or borders and considered the land between the two nations as Apache land. Due to the raids and capture of both goods and people on both sides of the border the U.S. and Mexico worked together and had a reciprocal agreement across the border to drive the Apache out of their lands. The border then became, again, a significant line for both the U.S. and Mexico.

The above is an example of an era in which there was focus on the border, but times change quickly and for almost a decade both the U.S. and Mexico had bigger problems at hand the focus on the border faded, at least for a time. Mexico soon found itself fighting to maintain control of its own country as the French had sent Archduke Ferdinand Maximilian to rule Mexico and the U.S. found itself in the middle of its own civil war. Those events lead both countries to shift focus away from the border and deal with their bigger problems at hand. Of course, as soon as those issues were resolved the border immediately came back into focus as another source of contention soon arose, the Apache playing the U.S. and Mexico against each other. The Mexican government blamed the U.S. for not controlling the Apache “on their own side of the border” as the Apache found it easier to raid in Mexico territory and then move back across the border into U.S. territory.

Both the U.S. and Mexico had finally proven that they had the ability to protect their borders from not only the Apache, but also from each other. Mexico soon passed legislation that prohibited U.S. citizens from owning property in Mexico but with the railroad system bringing new opportunities to the borderlands, something had to give and concessions made. Although there was not a struggle to “control” Mexico was known to have stores of valuable metals and ores in its mines that Americans were eager to obtain. Laborers from both countries flooded in by the thousands hoping to strike it rich in the mines and laborers were allowed to freely cross the border.

During the early nineteen hundreds both the U.S. and Mexico again began to realize how important the border was when it came to collecting customs, rejected unauthorized immigrants, and arrested criminals as the borderlands had seen an unprecedented growth with the development of a stable railway system. As the population boomed along both sides of the border the line became so much more important economically for both sides. Due to boundary disputes and disintegrating markers the U.S. and Mexico once again had to work together to resurvey and remap the boundary that separated the two countries. Since there were buildings physically on both sides of the border in towns like Nogales the U.S. and Mexico agreed that there should be a strip of vacant land at least 50 feet wide that separated the two countries along the border. This, to say the least, marked the beginning of the end for the binational friendly relationship that the U.S. and Mexico and been building up for the last several decades. That very physical separation was the beginning of what we see today with the fences and blockades between the U.S. and Mexico.

The civil war that tore Mexico apart also had a direct impact on the border between the two countries in that U.S. citizens began to worry that simple little monuments that marked the territory between the two countries could hardly keep U.S. citizens safe if the fighting spilled over into U.S. soil. The American government had no choice but to start sending troops to the border to not only protect Americans on U.S. soil but to also control the massive influx of immigrants trying to escape the violence that the Mexican civil war was inflicting on its citizens.

There were other events during the early to mid-nineteen hundreds that spurned other border control issues like prohibition. The U.S. and Mexico worked together and established controlled ports of entry into each other’s countries in an effort to minimize illegal immigration as well as smuggling of illegal items. Controlling import taxes was another benefit of the customs border entry points and eventually the border evolved into what it is today.

John, Rachel S. Line in the Sand: A History of the Western U.S.-Mexico Border. Princeton: Princeton University Press, 2012.