"The word for 'border' in English and Spanish reveals a philosophical divide. While in English, 'border' connotes a boundary that delineates a fixed separation that can serve as a barrier to the outside, in Spanish the word is 'frontera' which can also mean 'frontier'--or the beginning of a new territory. In Mexico's colloquial Spanish, 'the border' is often called 'la linea,' or 'the line,' which implies something arbitrarily drawn by a subjective hand. Indeed, many leaving Mexico today see the area beyond the northern frontier as a zone of relative safety, a crossing of the line in the hope of finding peace that is elusive at home because of drug cartel and gang violence. They are 'narco-refugees.' [...] Since 2006, when Mexican president Felipe Calderon declared war on the drug cartels, there has been a rise in the number of Mexican nationals seeking politcal asylum in the United States to escape the ongoing drug cartel violence in their home country."
Strategic Studies Institute: http://www.strategicstudiesinstitute.army.mil