Throughout this period, America's position as the dominant ideological force in prosecuting the war on drugs went unchallenged. They took the war south and met little resistance. Often, they were welcomed by countries that accepted help in combating drug cartels.

But that mood is starting to shift and America's position is now being challenged, increasingly and vociferously, by its neighbours in South and Central America. They have seen drugs, and the attendant war, pulverise and very nearly break a succession of countries in the region. There is a growing sense that the "drug-producing" nations in Latin America are bearing the brunt of the violence while the "drug-consuming" nations (principally America and in Europe) remain relatively unscathed.

This message will be delivered with force during the Summit of theAmericas, which will be attended by the leaders of 36 countries, including President Obama, later this week in Colombia. As our story reveals, all the countries of the Americas will sit down and, for the first time, have a formal discussion about the war on drugs. They will try to reach a formal agreement to study new, evidence-based approaches to tackling drugs – everything from a new war on drugs to complete legalisation. This is a watershed moment.