How can drug trafficking be controlled? The Drug Enforcement Agency has tried to limit the drug trafficking problem coming from countries south of the U.S. Also many other law enforcement agencies. The southern hemisphere has given the U.S. a really hard time with the international drug trade. Where do drugs come from? Most of the marijuana Smuggling routes that come into the United States comes from the south. Columbia is one of the main contributors to the problems of the drug war. Not only does Columbia sell cocaine to the United States, it also sells marijuana. Columbia is responsible for over eighty percent of the cocaine distribution around the world. In Columbia co