While U.S. leaders have focused on actual or illusory security threats in distant regions, there is a troubling security problem brewing much closer to home. Violence in Mexico, mostly related to the trade in illegal drugs, has risen sharply in recent years and shows signs of becoming even worse. That violence involves turf fights among the various drug-trafficking organizations as they seek to control access to the lucrative U.S. market. To an increasing extent, the violence also entails fighting between drug traffickers and Mexican military and police forces. The carnage has already reached the point that the U.S. State Department has issued travel alerts for Americans traveling in Mexico. U.S. tourism to cities on Mexico's border with the United States, where the bloodshed has been the worst, has dropped sharply. Even more troubling, the violence is spilling across the border into communities in the southwestern United States. U.S. officials, alarmed at the growing power of the Mexican drug cartels, have pressured the government of Felipe Calderon to wage amore vigorous anti-drug campaign. Calderon has responded by giving the army the lead role in efforts to eliminate the drug traffickers instead of relying on federal and local police forces, which have been thoroughly corrupted by drug money. Washington has rewarded Calderon's government by implementing the initial stage of the so-called Merida Initiative. In June 2008, Congress approved a $400 million installment modeled on Plan Colombia, the anti-drug assistance measure for Colombia and other drug-source countries in the Andean region. That program, now in its ninth year, has already cost more than $5 billion, without significantly reducing the flow of drugs coming out of South America. The Merida Initiative will likely cost billions and be equally ineffectual. Abandoning the prohibitionist model of dealing with the drug problem is the only effective way to stem the violence in Mexico and its spillover into the United States. Other proposed solutions, including preventing the flow of guns from the U.S. to Mexico, establishing tighter control over the border, and (somehow) winning the war on drugs are futile. As long as the prohibitionist strategy is in place, the huge black market premium in illegal drugs will continue, and the lure of that profit, together with the illegality, guarantees that the most ruthless, violence-prone elements will dominate the trade. Ending drug prohibition would de-fund the criminal trafficking organizations and reduce their power.