Summary: Illegal drugs continue to flood the United States despite long-standing efforts and expenditures of billions of dollars. U.S. counternarcotics efforts have led to the arrest of major drug traffickers, the seizure of large quantities of drugs, and the eradication of illicit drug crops; however, these efforts have not materially affected the availability of drugs on U.S. streets. The United States confronts several obstacles to combatting illegal drugs. International drug-trafficking organizations are sophisticated, multibillion-dollar industries that quickly adapt to new U.S. drug control efforts. As success is achieved in one area, the drug traffickers change tactics, thwarting U.S. efforts. Moreover, counternarcotics efforts in drug-producing and -transiting countries are hindered by corruption, competing economic and political policies, inadequate laws, limited resources, and internal strife, such as terrorism and civil unrest. For its part, the United States has been unable to maintain a well-organized and consistently funded international counternarcotics program. U.S. efforts have also been hampered by competing U.S. foreign policy objectives, organizational and operational limitations, and the lack of clear goals and objectives. Some foreign countries, with U.S. assistance, have tried to strengthen their ability to combat the flow of illegal drugs into the United States. It is too soon, however, to determine their impact.