Wait, the U.S. is making Mexican security officials take polygraph tests?

Fraying cooperation in the drug war will surely be top of mind as President Obama meets with his counterpart Enrique Peña Nieto in Mexico this week. And perhaps nothing encapsulates Mexico’s growing impatience with America’s heavy-handed approach to combating drug trafficking than this nugget from a New York Times report on Tuesday. Apparently, the United States has been subjecting Mexican security officials to regular polygraph tests in an effort to identify rotten apples. But that could soon change:

Shortly after Mexico’s new president, Enrique Peña Nieto, took office in December, American agents got a clear message that the dynamics, with Washington holding the clear upper hand, were about to change.

"So do we get to polygraph you?" one incoming Mexican official asked his American counterparts, alarming United States security officials who consider the vetting of the Mexicans central to tracking down drug kingpins. The Mexican government briefly stopped its vetted officials from cooperating in sensitive investigations. The Americans are waiting to see if Mexico allows polygraphs when assigning new members to units, a senior Obama administration official said.

While the practice is not widely publicized, it has been an element of the two countries’ security relationship for some time. In a 1997 article on U.S.-Mexican plans to join hands in the drug war, the Associated Press noted that Mexican counternarcotics agents would undergo the "kind of extensive background, financial, and polygraph tests required of U.S. drug agents." The plans came after the arrest of Mexico’s drug czar, Gen. Jesús Gutiérrez Rebollo, for taking bribes from drug traffickers.

What’s more, the United States hasn’t just applied this policy to Mexico. In 2012, the Los Angeles Times reported that Washington has given elite Colombian counternarcotics agents polygraph tests as well. 

The bad blood over polygraph tests isn’t the only sign that U.S.-Mexican cooperation on the drug war is deteriorating. In an interview with the Spanish news agency EFE on his new book, the Mexican journalist Jesús Esquivel claimed that the Mexican military recently waved off a U.S. offer to capture famed drug lord Joaquín "El Chapo" Gúzman. The United States had the Sinaloa cartel chief’s location and said the operation would take only 15 minutes. So why the hang-up? Mexican military officials reportedly didn’t want the American military to lead the operation.