As President Bush prepares to travel to Latin America, one of the top issues for discussion will be the war on drugs. The Bush administration is especially alarmed at the situation in Colombia, fearing that the democratic political system in that country could collapse under an assault by leftist insurgencies allied with powerful drug traffickers. Washington’s nightmare scenario is the emergence of a Marxist/​narcotrafficking state. U.S. leaders are so worried about that possibility that they are ready to expand America’s military aid to Bogota and eliminate the restriction that the aid must be used only for counter-narcotics campaigns, not counterinsurgency campaigns.

The fears about Colombia are not unfounded, but U.S. policymakers have a serious problem brewing much closer to home. The prominence of the drug trade in Mexico has mushroomed in recent years. Just two years ago, Thomas Constantine, head of the Drug Enforcement Administration, told Congress that the power of Mexican drug traffickers had grown “virtually geometrically” over the previous 5 years and that corruption was “unparalleled.” Matters have grown even worse in the past two years.

As is often the case with lucrative black markets, the illicit drug trade in Mexico has been accompanied by escalating corruption and violence. In a number of troubling ways, Mexico is beginning to resemble Colombia a decade or so ago. Indeed, Mexicans are beginning to refer to the trend as the “Colombianization” of their country. True, Mexico does not face a large-scale insurgency like that afflicting Colombia, but the similarities of the two countries are greater than the differences.

U.S. policy seems to assume that if the Mexican government can eliminate the top drug lords, their organizations will fall apart, thereby greatly reducing the flow of illegal drugs to the United States. Thus, U.S. officials have rejoiced at the recent capture of Benjamin Arellano Felix–the leader of one of Mexico’s largest and most violent drug gangs-and the apparent killing of his brother.

But that is the same assumption that U.S. officials used with respect to the crackdown on the Medellin and Cali cartels in Colombia during the 1990s. Subsequent developments proved the assumption to be erroneous. The elimination of the Medellin and Cali cartels merely decentralized the Colombian drug trade. Instead of two large organizations controlling the trade, today some 300 much smaller, loosely organized groups do so.

The arrests and killings of numerous top drug lords in both Colombia and Mexico over the years have not had a meaningful impact on the quantity of drugs entering the United States. Cutting off one head of the drug-smuggling hydra merely results in more heads taking its place.

Of all the similarities between Colombia and Mexico, the most troubling may be the increasingly pervasive violence. It is no longer just the cocaine and heroin trade that is characterized by bloodshed. Even the marijuana trade, which traditionally had generated little violence, is now accompanied by horrific killings. Indeed, the biggest and bloodiest massacres over the past three years in Mexico have involved marijuana trafficking, not trafficking in harder drugs.

Mexico can still avoid going down the same tragic path as Colombia. But time is growing short. If Washington continues to pursue a prohibitionist strategy, the violence and corruption that have convulsed Colombia will increasingly become a feature of Mexico’s life as well. The illicit drug trade has already penetrated the country’s economy and society to an unhealthy degree. The brutal reality is that prohibitionism simply drives commerce in a product underground, creating an enormous black-market potential profit that attracts terrorists and other violence-prone elements.

U.S. officials need to ask whether they want to risk “another Colombia”–only this time directly on America’s southern border. If they don’t want to deal with the turmoil such a development would create, the Bush administration needs to change its policy on the drug issue — and do so quickly.