Disputes - international: abundant rainfall in recent years along much of the Mexico-US border region has ameliorated periodically strained water-sharing arrangements; the US has intensified security measures to monitor and control legal and illegal personnel, transport, and commodities across its border with Mexico; Mexico must deal with thousands of impoverished Guatemalans and other Central Americans who cross the porous border looking for work in Mexico and the United States
Illicit drugs: major drug-producing nation; cultivation of opium poppy in 2007 rose to 6,900 hectares yielding a potential production of 18 metric tons of pure heroin, or 50 metric tons of "black tar" heroin, the dominant form of Mexican heroin in the western United States; marijuana cultivation increased to 8,900 hectares in 2007 and yielded a potential production of 15,800 metric tons; government conducts the largest independent illicit-crop eradication program in the world; continues as the primary transshipment country for US-bound cocaine from South America, with an estimated 90% of annual cocaine movements toward the US stopping in Mexico; major drug syndicates control the majority of drug trafficking throughout the country; producer and distributor of ecstasy; significant money-laundering center; major supplier of heroin and largest foreign supplier of marijuana and methamphetamine to the US market (2007)