One of the ways that this text witnesses to the nature of voluntary immigration is through the efforts of the US Border Agency to keep such "voluntary migrants" out of their country. It is interesting to analyse the kind of language that is used to describe the "rush" of illegal immigrants into America. When describing Southern Arizona, for example, Urrea uses the metaphor of the Border Patrol in recent years being "hammered by growing tidal waves of illegals." This is a very powerful metaphor to use, suggesting an unstoppable rush of illegal immigrants. Note the following paragraph, which details the sheer number of objects that are being used to try and stop this onslaught:

Bigger fences, floodlights, a Border Patrol truck every half-mile, sensors, infrared spy videos, night vision cameras, Immigration and Naturalization Service checkpoints on all major freeways in and out of town, more agents.

The asyndetic listing here helps emphasise the extent of this "invasion" and the way that the US is trying desperately to catch up with the sheer numbers that are pressing into their territory. What is so disturbing about this text is the way that Urrea paints a picture of so many immigrants who will do anything, even get themselves into massive debt and risk their lives, for the chance to go and live and work in the States, which is seen as the land of opportunity.