The North American Free Trade Association has accelerated its interdependence with the U.S. economy. At the same time, Mexico has been experiencing great political, economic, and social disruption, and has become the territory of origin or transit of most of the illegal drugs entering the United States. The growing interpenetration and interdependence of the two countries means that this turmoil is more likely than ever to spill over the border. Whether in the form of economic interaction, illegal immigration, or the spread of corruption and violence, what happens in Mexico increasingly affects our own national interests. By redefining U.S.-Mexican national security in nontraditional terms, the author has gone a long way towards helping us comprehend the implications of what has been happening. Equally important, he offers practical suggestions as to how U.S. leaders should respond—and not respond—to these challenges.