In 2011, the United States ambassador to Mexico, Carlos Pascual, became the first American ambassador forced to resign. A series of cables sent by Mr. Pascual to Washington, and published by WikiLeaks, revealed that when the American authorities detected the location of a high-value target, they were made to choose between several unpalatable alternatives: Notify the Mexican Army, which might tip off the target and was risk-averse; notify the federal police, which was essentially paralyzed; or notify the United States-trained Navy, which was effective but exceedingly violent.

This conundrum was often resolved by embedding American agents in the teams going after kingpins, and sharing intelligence only with Mexican forces highly vetted by the Americans beforehand.

One possible explanation for the humiliating defeat suffered by the Mexican military and President Andrés Manuel López Obrador last week in Culiacán, Sinaloa, where government forces caught and then released a major drug lord, may lie in these precedents. There is no proof that the American authorities located Ovidio Guzmán López , known as “little Chapo” or “Chapito,” but if so, it would follow a pattern.

His father, the drug lord known as El Chapo, Joaquín Guzmán Loera, was captured twice thanks to Drug Enforcement Administration intelligence. As were other high-value targets like Edgar Valdez-Villareal, known as “La Barbie,” arrested in 2010, and Arturo Beltrán Leyva, killed in 2009.