This dissertation analyzes the connection between Mexican out-migration to the US and Mexico’s ongoing internal wars during the process of US securitization and criminalization of undocumented migration. Until now Mexico’s transition to democracy has been the primary explanation for the spike in levels of criminality in Mexico dominating the literature. However, this dissertation argues that the financial crisis and a decade of hostile US security policies marked by a record high in deportations has discouraged Mexican outmigration to the US. In doing so, these policies have removed an important counterweight to narcotrafficking and ended up by helping the Mexican criminal organizations which they were claiming to fight. For decades, Mexican irregular migration to the US turned a problem into an opportunity for Mexico since remittances promoted peace and development, and the departure of unsatisfied people stimulated social and political stability, particularly in the Mexican countryside. Nevertheless, during the 2000s, post 9/11 migration and security policies in the US greatly reduced this 'escape valve' and ended the 'American Dream'. Therefore, by restricting one of the main strategies for capital and status acquisition and one of the main alternatives from the 'repertoire of adventures' for young males, Mexico became more violent. A statistical analysis of the changes in the average number of homicides and migration data in two periods (1995 - 2000 and 2005 -2010) combined with semi-structured interviews and participant observation in regions of migration origin are used to provide evidence about the connection between the end of the 'American Dream' and 'the Mexican Nightmare'. In addition, time-series data at the state and community levels are combined with ethnographic and journalistic material to provide analytical narratives about the trajectories followed by the migrant communities in three states. A controlled comparison selecting three Mexican states with strikingly similar socioeconomic and political characteristics but different levels of outxxiv migration and violence is conducted. At last, the consequences of European migration policies on Moroccan migration to the EU are analyzed in order to address the external validity of the proposed theory beyond the Mexican case. Such a mixed methods approach allows to identify certain nuances in social sciences that are usually not addressed simultaneously by works that do not bridge the quantitative-qualitative divide. In particular, this thesis identifies heretofore neglected variables as salient: increased competition for local scarce resources; deflection of prospective migrants into dangerous occupations like growing illegal crops; reactivation of blood feuds since paying back debts became more difficult; a fall in school attendance because parents were not able to sustain their children economically once they were impeded from sending remittances; and reduction in seasonal economic spillovers produced by migrants during holidays.