In the most recent Perry Center Occasional Paper, “Measuring the Success in the War on Drugs,” Professor Pat Paterson and research assistant Katy Robinson assess counternarcotic strategy in the Western Hemisphere. Tracking coca cultivation and cocaine trafficking in the region, the authors trace the illicit products as they are cultivated in the Andes Mountains of South America, processed into cocaine in Colombia and Peru, transported through Central America and Mexico, and finally delivered to markets in the United States. At each phase, they examine empirical evidence that indicates the level of effectiveness of counternarcotics trafficking programs. Their analysis, spawned by the calls for policy reform from the Global Commission on Drug Policy and other Latin American leaders, was motivated in part by the need to sift through the rhetoric surrounding the war on drugs. Using official government statistics (including never-before publicly released information), the authors conclude that the US and its partner nations are accomplishing results in some aspects of the counternarcotics efforts—such as reduced coca cultivation in the Andean nations and reduced cocaine use and consumption in the US—but are failing to achieve objectives in other important parts of the supply reduction strategy (e.g., interdiction successes in the transit zone).