While historians in the United States tend to focus on the contemporary issue of immigration, the focus less frequently on the economic history between the United States and Mexico, which combined to form the underlying catalysts of immigration. Two noted scholars that researched underlying key aspects of immigration and are referenced in this paper are Lawrence Cardoso and David Gutíerrez. Cardosos argument states that the industrialization policies implemented by President Porfirio Diaz were the first initial catalysts of Mexican immigration. These policies brought about rapid change in land and labor systems, resulting in the massive immigration. In Gutíerrezs argument, he states that the growing southwestern economy, its call for labor, and the expansion of railroads attracted the displaced Mexican rural farmers, who struggled as a result of industrialization policies. This research paper discusses both catalysts, what occurred in the United States and Mexico, and what tied them together, arranged chronologically in order to gain a better perspective.
In Cardosos Porfirian Mexico: The Background of Massive Emigration primarily concentrates on economic events that occurred in Mexico, starting at the levels of the Mexican elite and working down towards the rural and poorer farmers of central Mexico. He tends to emphasize the impoverished farmers by describing the difficulties that they endured and how those hardships had led to the initial immigration. This differs from Gutierrezs concentration in Walls and Mirrors: Mexican Americans, Mexican Immigrants, and the Politics of Ethnicity. He states the labor demands, and more importantly railroads, greatly aided in the process of Mexican immigration and had increased the speed of development of the southwest economy. Though he writes that the economic shortcomings in the lives of Mexican rural farmers aided in immigration, without the incentives advertised by the United States, immigration would have been much slower. These two ideas form the basis of this research paper because when combined they offer a decisive and more concrete reason for the initial large-scale immigrations of Mexicans to the United States.
The Loss of Texas to the United States
Following the end of the Mexican-American War in 1848, the United States acquired about forty-five percent of Mexican territory under the Treaty of Guadalupe-Hidalgo, adding considerable territory to what constitutes the states of Texas, New Mexico, Arizona and California today. Between the Mexicans already in the United States as a result of land acquisition and numerous new communities established in close proximity to the border there was a Mexican presence well before North Americans began to become interested in their economic potential. At the end of the nineteenth century the dynamics of American interest in Mexican labor began to strengthen due to the rapidly growing need for railroad construction. The Mexicans presented a significant source of manual agricultural labor due to Mexicos locality to the United States and its economic vulnerability to the Porfiriato industrialization policies.Mexico and the United States disputed the boundaries of the land acquired under the Treaty of Guadalupe Hidalgo. With the Gadsden Purchase of 1853, United States President Franklin Pierce was able to resolve the boundary dispute and to further his plans for westward expansion. He purchased from Mexico the Mesilla Valley, a 30,000 square mile area north of El Paso along the Rio Grande for $10 million, including what is now the city of Tucson, Arizona. From here railroads could be built east to El Paso and west to the Pacific. Moving the railroads farther north would result in a greater expanse of economic trade and increased industry. And this coupled with the large-scale immigration of rural Mexican farmers would yield a historic period of economic growth in the United States.
 PBS The Border, The Gadsden Purchase is Signed, http://www.pbs.org/kpbs/theborder/history/index.html.