"Efforts to significantly reduce the flow of illicit drugs from abroad into the United States have so far not succeeded. Moreover, over the past decade, worldwide production of illicit drugs has risen dramatically: opium and marijuana production has roughly doubled and coca production tripled. The effectiveness of international narcotics control programs in reducing consumption is a matter of ongoing concern. Despite apparent national political resolve to deal with the drug problem, inherent contradictions regularly appear between U.S. anti-drug policy and other national policy goals and concerns. Pursuit of drug control policies can sometimes affect foreign policy interests and bring political instability and economic dislocation to countries where narcotics production has become entrenched economically and socially. Drug supply interdiction programs and U.S. systems to facilitate the international movement of goods, people, and wealth are often at odds. U.S. international narcotics policy requires cooperative efforts by many nations that may have domestic and foreign policy goals that compete with the requirements of drug control. One contentious issue has been the congressionally-mandated certification process, an instrument designed to induce specified drug-exporting countries to prioritize or pay more attention to the fight against narcotics businesses. Current law requires the President, with certain exceptions, to designate and withhold assistance from countries that have failed demonstrably to meet their counternarcotics obligations."
CRS Report for Congress, RL33582
U.S. Department of State: http://fpc.state.gov/