Operation Trizo was a joint Mexican-American campaign directed against drug traffickers within Mexican territory. It lasted from November 15, 1975, to April 10, 1978, when the Mexican government secured the departure of all DEA spotters. While Mexican soldiers and federal police on the ground arrested, killed, or extorted anyone suspected of producing or smuggling drugs, Mexican and American pilots sprayed marijuana and poppy fields with herbicides from the air. The destruction of illegal fields in particular had an unprecedented effect, making Operation Trizo the most successful anti-drug campaign in the country’s history—but only to a certain extent.

Although the vast majority of anti-drug efforts anywhere in the world end in failure, there have been a few seemingly successful campaigns. These, however, always prove to be Pyrrhic victories that ultimately change only one thing: in accordance with the well-known balloon effect, they shift control of the narco-business to another region. Operation Trizo was no exception. Once it subsided, criminals from South America and Asia took over the American marijuana and heroin market from the decimated Mexican trafficking organizations.

Not only was the shortage of illicit substances on American streets merely short-lived, but the number of civilian casualties in Mexico may have even exceeded the temporary reduction in heroin overdose deaths in the United States. During Operation Trizo, Mexican soldiers and police committed brutal human rights violations that some DEA agents described as atrocities.

This collection contains 284 documents (diplomatic cables) divided into six parts. All documents indirectly follow on from Diplomatic Cables 1975; this time, however, they primarily concern the two-and-a-half-year-long Operation Trizo. The messages provide testimony about the Mexican government’s initial reluctance to intensify the fight against traffickers, particularly when it came to the use of herbicides advocated by Washington. The documents also reveal detailed information about the unprecedented successes in destroying fields, as well as tragic aviation incidents and the financial circumstances surrounding the entire operation.