Kelly Lytle Hernández's book Migra! A History of the U.S. Border Patrol provides the first book-length treatment of the primary enforcement arm of United States immigration law. Hernández traces the Border Patrol from its unsteady beginnings in the 1920s to its entrenched position in the 1970s. In its first phase, the Border Patrol had little funding and no clear mandate. Officers were supposed to prevent unlawful entry, but they were not given any guidance about how to do so. The early Border Patrol was a distinctly local project, staffed almost completely by border residents and therefore heavily influenced by the distinct racial logic of the borderlands. The early patrolmen chose to focus their efforts on policing and controlling the Southwest's largest source of labor: Mexican migrants. As Hernández notes, it was not a foregone conclusion that the Border Patrol would concentrate on unlawful entrants of Mexican descent. During the 1920s there were migrants of many different nationalities seeking to cross the border, and there were various classes of migrants who were “illegal” because of factors such as poverty, disease, or criminal behavior. The patrolmen could have made these unlawful entrants a priority, but instead they focused almost exclusively on tracking down and removing Mexican laborers, using racial profiling, harassment, coercion, and violence in the process.

With the upheavals of the Depression and World War II, the organization faced new pressures and renewed interest from Washington, D.C. For the first time, the Patrol gained national, rather than just regional, importance. “Old-timers” were replaced by new recruits, and old methods of control were replaced by new technologies. In one of the most interesting themes of the book, Hernández describes how violence never disappeared as a method of immigration control, but rather took on new, more sanitized and socially-acceptable guises. It was no longer permissible for officers to act as erstwhile Texas Rangers, using explicit threats of violence and intimidation. Instead, they began to erect strategically-placed fences at the main entry points. These fences had the effect of pushing migrants to dangerous, unpopulated desert areas, where scores died each year. The patrolmen also altered their methods of deportation: instead of simply dropping migrants off across the border or sending them directly to their hometowns, they began sending them by bus, train, or boat to isolated and unfamiliar areas deep in the interior of the country, leaving migrants vulnerable to exploitation and abuse. As Hernández writes, the new dangers were not “men with guns,” as in the early years, but instead these less direct, but by no means less deadly, methods of policing and enforcement (132).

Migra! is part of a recent and welcome trend in the history of immigration law, toward law “on the ground” rather than only in the halls of Congress or the courtroom. Hernández's book is part of this trend, yet it stands alone in the unique transnational perspective that it brings to the history of immigration law. Hernández has uncovered a trove of materials about the Mexican equivalent of the immigration service, known as the Mexican Department of Migration. With these she is able to demonstrate the effects that United States immigration law had on Mexican policies, and vice versa. One of the most striking findings is the influence that the Mexican government had over the direction of United States enforcement policy in the 1940s and 1950s. Before this period, Mexico had largely embraced, or at least accepted, the emigration of its laborers to farms in the United States. As Congress placed more restrictions on Mexican migration, however, the Mexican government found itself with a growing problem: too few laborers for its own farms and industries, and too many immigrant smugglers, destitute deportees, and dislocated families. The Mexican government encouraged the United States to increase efforts to prevent unlawful entries from Mexico. The Mexican authorities worked directly with the United States Border Patrol, arresting migrants who arrived at the border without proper papers, placing deportees on trains bound for the interior, and even at times shaving the heads of repeat offenders.

The Border Patrol's focus on policing Mexican migrants therefore intensified in the 1940s and 1950s, ironically, with the help of the Mexican government itself. By the 1970s, the Border Patrol had entered yet another new phase, having reinvented itself as an organization positioned to fight crime, not just control migration. The various projects of drug, crime, and migration control became increasingly entangled. This change in tone coincided with the increasing criminalization of migrants themselves, a process that continues today.

Migra! will be a useful resource for any scholar seeking to understand the complex dynamics of race, migration, and law in the twentieth century. The border and the people patrolling it provide for a rich and provocative way to explore these issues, both in historical and contemporary perspectives.