From Sanctions Wiki
Major drug-producing or drug-transit country
September 15, 2011 - Under the Foreign Relations Authorization Act (FAA), the President is required each year to notify Congress of those countries he determines to be major illicit drug-producing countries or major drug-transit countries that significantly affect the United States. A country’s presence on the list does not necessarily reflect its counternarcotics efforts or its level of cooperation on illegal drug control with the United States. The designation can reflect a combination of geographic, commercial, and economic factors that allow drugs to be produced and/or trafficked through a country.
When a country on the list does not fulfill its obligations under international counter-narcotics agreements and conventions, the President determines that the country has failed demonstrably to meet its counterdrug obligations, only Bolivia, Burma, and Venezuela, failed demonstrably. Such a designation can lead to sanctions. However, the President may also execute a waiver when he determines there is a vital national interest in continuing U.S. assistance. Even without such a waiver, humanitarian assistance and counternarcotics assistance may continue.