U.S.-Mexico relations were rattled Wednesday by reports of a Drug Enforcement Administration (DEA) investigation into drug money connections to Mexican President Andrés Manuel López Obrador’s 2006 campaign.

Three distinct reports, published by ProPublica, InSight Crime and Deutsche Welle (DW), expanded on previous allegations that López Obrador aides took millions of dollars from drug cartels in 2006 in exchange for a promise of lax law enforcement if he came to power.

López Obrador on Wednesday and Thursday railed against the reports, alleging a State Department-led media conspiracy against him.

“In the case of the United States, the State Department and the agencies have a lot of influence in the management of media, and also here, but there is no proof. They are vile slanderers, although they are rewarded as good journalists,” he told reporters at his daily press conference Wednesday.

The reports brought to the surface old grievances that López Obrador has against his political rivals and the United States at a time when President Biden has been actively courting the irascible Mexican president for cooperation on migration enforcement.

The DW report alleges López Obrador placed a thank you call to Edgar Valdez Villarreal — a U.S. citizen known as “La Barbie” who at the time led the Beltrán Leyva Organization — for facilitating contributions between $2 million and $4 million to his campaign.

The Beltrán Leyva Organization at the time was allied with the Sinaloa Cartel under an umbrella group named “La Federación.”

ProPublica and InSight Crime reported that the DEA never established whether then-candidate López Obrador knew of the scheme.

But all three reports, produced independently of one another, conveyed essentially the same story: that DEA agents carried out an investigation that placed López Obrador’s longtime aide Nicolás Mollinedo at the center of the scheme to receive campaign contributions from La Barbie.

The investigations were overseen by the Sensitive Activity Review Committee (SARC), where Department of Justice (DOJ) and DEA officials direct politically sensitive operations.

In 2011, shortly before López Obrador lost his second presidential election to former President Enrique Peña Nieto, SARC pulled the plug on the Mollinedo investigation.

Peña Nieto, then the front-runner, was seen as less accepting of U.S.-Mexico security cooperation than former President Felipe Calderón’s, under which the two countries signed the Mérida Initiative to jointly combat drug trafficking.

That attitude, according to the reports, made U.S. officials less bullish about pursuing an investigation tied to López Obrador, a major political figure in Mexico.

“In the 21st century, one would hope that what we had been building — starting in 2006, but mainly in the aftermath of the terrorist attacks against the U.S. in 2001, which was, I think, the big transition moment in the security and intel relationship between Mexico and the United States — that that’s the type of relationship that we need today,” said Arturo Sarukhán, who served as Calderón’s 2006 foreign affairs campaign adviser and as Mexican ambassador to the United States from 2007 to 2013.

But following the recent reports, López Obrador railed against deepened security cooperation, implying that Genaro García Luna, Calderón’s now-convicted former top security official, ran the Mexican government during Calderón’s term.

“About the DEA and other agencies involving themselves [in Mexican politics], of course they involve themselves, and more when they’re allowed, as it happened precisely during the government of — I don’t know whether to say Calderón or García Luna — then, they entered the country and did whatever they wanted. So that doesn’t happen anymore and that has them angry,” López Obrador said Wednesday.

García Luna in 2023 was convicted of receiving bribes and using his position to aid the Sinaloa Cartel, in a case that his lawyer described as “built on the backs of some of the most notorious and ruthless criminals to testify in this courthouse.”

López Obrador and officials in his administration celebrated García Luna’s conviction, portraying it as proof that Calderón, López Obrador’s arch-nemesis, was corrupt.

Days ahead of the three reports on the 2006 campaign, the Mexican attorney general revived an old case — the assassination of Mexican presidential candidate Luis Donaldo Colosio in 1994 — naming a security agent who was then under García Luna’s command as an alleged second shooter.

Sarukhán called the attorney general’s new revelations “a smoke and mirrors operation” to distract from the stories, all of which had reached out for comment from López Obrador’s office on several occasions.

“If you want a smoking gun, that to me is a smoking gun. It says that at least the Mexican government and the office of the president was very concerned and very uncomfortable by the information that these three outlets published,” said Sarukhán.

The Biden administration has stayed away from addressing the allegations directly, but a person familiar with the situation downplayed the probe, saying, “The investigative activity was limited in time, constrained in scope to only drug-related criminal activity, noticed in-country, and concluded.”

In other words, U.S. officials in Mexico and Mexican officials were informed of the investigation before it was shut down.

Officially, DOJ touted its law enforcement cooperation with Mexico.

“The Justice Department fully respects Mexico’s sovereignty, and we are committed to working shoulder to shoulder with our Mexican partners to combat the drug cartels responsible for so much death and destruction in both our countries. It is our standard practice not to comment on the existence of any particular investigative activity. We consistently follow strict internal protocols and oversight for handling all sensitive, international investigations,” a spokesperson told The Hill.

López Obrador on Thursday complained that the Biden administration turning the page was not enough, since the reports were sourced to several U.S. officials.

“That’s an informal question, I don’t accept that. What I want is for the government of the United States to manifest itself, because the president of Mexico has moral authority and has political authority. And if they don’t have proof, they have to apologize,” he told reporters.

Though López Obrador said the allegations in the reports are untrue and amount to libel, calling ProPublica’s Tim Golden “a mercenary at the service of the DEA,” he declined to call for charges against the outlets or the reporters involved.

“He’s a pawn, a mercenary of journalism, like they exist in Mexico, they exist in the United States and all over the world, but that has to do with the Department of State, because it’s also not the DEA [by itself], abstractly. What, don’t they have information in the Department of State, in the Department of Justice?”

Those accusations and López Obrador’s position that the reports were somehow engineered by the U.S. government could threaten bilateral cooperation, amid growing Democratic concerns about the role of migration in the 2024 presidential election.

“They know,” said López Obrador of Biden administration officials.

“President Biden should know about this because how are we going to be sitting at the table talking about combatting drugs, if they or one institution of theirs is leaking information and hurting me? Not me, what I represent,” he said.

Mexico, like the U.S., is facing a presidential election this year, and though López Obrador can’t run for reelection, he is pushing for his chosen successor, former Mexico City Mayor Claudia Sheinbaum, to win in June.

Sheinbaum’s opponent, opposition candidate Xóchitl Gálvez, on Wednesday took López Obrador at his word. 

Gálvez called Golden a “very prestigious journalist” but said López Obrador should open a criminal complaint in the United States if he believes the reports are libelous.

“It’s a very grave accusation against the head of the Mexican state,” she said. “He is obligated to present a criminal complaint before the United States, because they are accusing the head of the Mexican State.”

—Updated Friday at 10:28 a.m.