ABSTRACT
As we wrote this chapter, the U.S. government approved plans to build a 700-milelong wall along our southern border with Mexico. Despite disapproval by people living in close proximity in the states on both sides of the border, illustrated by the billboard shown in Figure 20.1, Congress and President Bush have decided that a wall between the two countries is needed to prevent immigrants from Mexico and other countries from entering the U.S. illegally.
