Miguel Ángel Treviño, the leader of the Zetas, Mexico’s most fearsome and brutal cartel, was arrested last night in Mexico near the U.S. border. This is the first major blow to organized crime in the seven month presidency of Enrique Peña Nieto.

Sylvia Longmire and Alejandro Hope [in Spanish] have good analyses on what the capture of Treviño will mean in the near and medium term to the Zetas and to the configuration of organized crime in Mexico. Overall, we should expect a spike in violence as the Zetas might splinter into several violent “cartelitos” which will fight one another for control of territory. Also, we might see a renewed effort from the Sinaloa cartel of Joaquín “Chapo” Guzmán to challenge the Zeta’s control of the lucrative Nuevo Laredo transit route.

But isn’t the ultimate goal of the war on cartels to stop the flow of drugs into the United States? Should we expect a decline in the smuggling of narcotics after the arrest of Treviño? No, according to reports from the U.S. government itself. The Office of Intelligence and Operations Coordination of the Custom and Border Protection agency looked at drug seizure data from January 2009 to January 2010 and matched it with the arrests or deaths of drug operatives (11 capos in total). It found that “there is no perceptible pattern that correlates either a decrease or increase in drug seizures due to the removal of key DTO [drug trafficking organization] personnel.”

The arrest of a nasty and blood thirsty criminal such a Treviño is good news for Mexico. But don’t expect it to tip the balance in the overall war on drugs.