Even people in the private sector, witnesses have said, took cash from the cartels.
A few weeks ago, the jurors learned that Mr. Guzmán had once reached a deal with a Colombian catering firm to sneak cocaine past security officials at the Bogotá airport onto planes owned by a Venezuelan airline, Aeropostal. When the planes arrived in Mexico City, the jurors were informed, a crew of corrupt employees would move the drugs onto trucks for the cartel.
Jorge Cifuentes Villa, a Colombian trafficker who also shipped cocaine to Mr. Guzmán, recently testified that, during his career, he laundered up to $15 million in drug-trade profits through a crooked debit card company.
Mr. Cifuentes also said he once paid off a professional gemologist to fraudulently certify that there were emeralds in a mine he had invested in and was using as a drug front.
Some of the most egregious evidence of corruption has not been heard by the jury, and likely never will be.
In November, for example, one of Mr. Guzmán’s former operations chiefs, Jesus Zambada García, was poised to reveal that two Mexican presidents — neither of whom was named — had taken massive bribes from the cartel. But the testimony was shut down before it could be heard by Judge Brian M. Cogan, who ruled that it would needlessly embarrass certain “individuals and entities.”
But further tales of payoffs may be coming.
In his opening statement, Jeffrey Lichtman, one of Mr. Guzmán’s lawyers, promised jurors that a witness who has not yet appeared at the trial, Cesar Gastelum Serrano, could — if asked — talk about bribing presidential candidates in Guatemala and buying off a president of Honduras.
Then there was another potential witness, Dámaso López Núñez, one of Mr. Guzmán’s top lieutenants, who allegedly had Mexican Marines, intelligence officers and local politicians on his payroll.
“There is no part of the Mexican government or law enforcement apparatus,” Mr. Lichtman said, “that Dámaso did not control.”