government continued pressuring the United States to strengthen its border security or face the suspension of the legal stream of Mexican laborers entering the United States. In October 1948, Immigration officials opened the Texas- Mexico border which allowed several thousand undocumented workers to cross the border. From here most workers were escorted by Border Patrol agents straight to the cotton fields. This event started the informal practice of using undocumented Mexican labor while the blacklist was in place. This incident was problematic due to the direct way the US government was involved in the managing and movement of these undocumented workers. This opening of the border was also in direct violation of previous agreements with the Mexican government. This incident would become known as the El Paso incident. Two million Mexican nationals participated in the program during its existence, but tensions between the program's stated and implicit goals, plus its ultimate ineffectiveness in limiting illegal immigration into the United States, eventually led to Operation Wetback in 1954. Illegal migration after 1942 Despite the Bracero program, American growers continued to recruit and hire illegal laborers to meet their labor needs. The program could not accommodate the number of Mexicans that wished to work in the United States. Many who were denied entry as a bracero crossed illegally into the United States in search of better wages and opportunity. Nearly 70% of people who were attempting to immigrate to America were denied because they were viewed as undesirable for a variety of reasons, including age, gender, or other factors. While the Mexican Constitution allowed citizens to cross borders freely with valid labor contracts, foreign labor contracts could not be made in the United States until an individual had already legally entered the country. This conflict, combined with literacy exams and fees from INS formed significant obstacles for Mexican laborers wishing to seek higher wages and increased opportunities in the United States. Food shortages were common in Mexico while most of the foodstuff produced was exported. Hunger and misgovernment, combined with population growth, prompted many Mexicans to attempt to enter the United States, legally or illegally, in search of wages and a better life. This growth was exponential, resulting in the population nearly tripling in a short time period of forty years. The Mexican government's interference with the privatization and mechanization of Mexican agriculture added more problems to finding employment in Mexico, providing