This chapter looks at the relationship between the United States and Mexico and the 'war on drugs' from 1940 to 1980. During this period, the United States, in particular its drug agencies, deployed a series of pressurizing mechanisms which shaped drug policy in Mexico, where the state developed a policy remarkable for its strong prohibitionist and punitive dimensions. The chapter examines how the 'war on drugs' began decades before Felipe Calderón announced his campaign in December 2006 and long before Richard Nixon did the same in 1973. It explains why public policies which had shown serious deficiencies from the start were met with little resistance from the governing elites. Finally, the chapter addresses the means by which the Mexican government exercised the punitive and prohibitionist policy proposed by the US to advance its process of nationalization and centralization in regions 'in the margin of the state' (Das and Poole 2004).