QUOTE : Often they are mentioned in the same breath as drugs that are smuggled across, or terrorists that might try to be. What crosses the border is dangerous; the Southwest is our 'exposed flank.' There is a nagging fear that we've gone to sleep with the back door unlocked.<br /><br />"In Mexico the migration is less imagined and more concrete. It's something people from the poorest and most remote corners of the republic have participated in for years -- at least as far back as 1848, when the United States, through the Mexican War and the Treaty of Guadalupe Hidalgo, acquired nearly half of their country, stranding many Mexican nationals in a foreign land. Then, as now, migration has been recognized to be a two-way street, of people leaving home for a while, working, and then mainly returning home. The relatively fast pace of American industrialization, coupled with Mexico's economic and demographic crises, has accelerated the movement north. Today, if you are among the majority of Mexicans -- those with very little money -- working in the United States is not merely something you hear about, but something you might consider. It is one of life's few options.