The U.S. and Mexico have been neighbors for more than two centuries. Despite intermittent attempts by Mexico to distance itself from the US out of a concern of US protectionism and its political, cultural and economic hegemony, a process of progressive economic and social integration has taken place among the two countries which expresses itself in high levels of trade, financial and labor flows. By 2001 some analysts and think tanks believed that sufficient progress had been achieved to propose a greater intensification of economic and social relations and even the creation of a North American Community. Multiple factors, however, have combined to dramatically transform the context of the relationship. The US and Mexico face a critical juncture in their economic, security, and social relations created by the US embarkation on a global War on International Terrorism after September 11, 2001, a sudden increase in levels of drug trade-related violence in Mexico, the US financial crisis stimulated by the collapse of the subprime mortgage market, challenges thrown up by the dramatic reach of the economic globalization process, failed efforts to integrate the Western Hemisphere, and the need to incorporate new social forces as a result of the beginning of democratization in Mexico and its further development in the U.S. Will the policies adopted by each country to address these challenges lead to further cooperation and deepening of economic and social integration or is the progress previously achieved likely to derail?