Instability
The imagery of instability shapes the motivations of these illegal immigrants (or perhaps refugees, one might say). How unstable is Mexico? Well, Urrea explains that in Mexico, if a gang terrorizes a certain family or community, the police will abandon them, so as not to be in conflict with the cartel. If the cartel decides to take over a town, the government will pack up and leave from that town in many cases. Then, jobs and homes are threatened. Sometimes the threat is so severe that people are not able to leave their homes without being assassinated or abducted.
Hope and risk
The imagery of risk shapes the motivations of these men as well. Even though it will mean risking their very lives, they still are forced to follow their need for hope and for a better future. One should already be able to tell that if they are willing to risk their own deaths to escape the instability of their Mexican hometowns, that they are entering the logical considerations of refugees. This is not the motivation pattern that one would expect from Mexicans, "coming to steal American jobs." This is the imagery of last hope.
The treacherous journey
The journey is extremely treacherous into America. Because of the efficiency of American Border Patrol, the immigrants are forced to make use of the desert which is so dangerous that even Border Patrol does not enforce it. There aren't enough natural resources to even sustain a serious Border Patrol presence—that is how dangerous and sparse the desert is there. This imagery also contains the risk of extreme temperatures, hungry predators, and of course, the risk of capture and arrest by United States officers.
The American opinion
The imagery that shapes the American opinion is the jail. The opinion among many Americans is that these men are not refugees (despite all the evidence that shows that they are), and that they are criminals who deserve to be arrested and sent back to Mexico. The irony of this imagery is that in some ways, jail is the safest place these men have been in the entire course of the book! The diversity of opinion and the controversy of these issues is also part of this imagery because of Urrea's own arguments and questions to the reader.