Iowa Sen. Chuck Grassley has been trying to get answers from these agencies, and on Thursday his office released a trove of documents from both whistleblowers and officials who responded to his demands for documents. While the material sheds more light on how the operation worked, they don't answer the fundamental question of why the Biden administration put a stop to it. 

The new documents, exclusively obtained by CBS News, were sent by Grassley on Thursday to nine federal law enforcement agencies within the Departments of Justice, Homeland Security, State and Postal Service. They accompanied a set of sternly-worded letters demanding that each department disclose details about Thor's operations — the existence of which the Biden administration has yet to publicly acknowledge — as well as all current efforts to target cartel firearms trafficking networks operating in the U.S. and neighboring countries.

"The American people deserve to know more about the Biden administration's strategy … to target cartel firearms networks in the U.S.," wrote Grassley, questioning exactly how committed the U.S. government has been to stem the flow of American weapons into the hands of cartels.

The FBI and State Department declined to comment. The Postal Service confirmed that they were reviewing the letter and "will be providing a response directly to the Senator."  In an email, Justice Department spokesman Peter Carr also acknowledged receiving Grassley's letter. 

... Grassley's newly released documents make public, for the first time, internal charts detailing how intricate networks of traffickers across the U.S. smuggle firearms and ammunition across the southwest border into Mexico and the hands of drug cartels, including depictions of actual narco weapons trafficking routes. 

This follows a CBS News investigation that revealed that Mexican drug cartels have been smuggling a vast arsenal of military-grade weapons out of the U.S. with the help of American citizens, including belt-fed miniguns and grenade launchers. Intelligence documents and interviews with half a dozen current and former officials showed that the U.S. government has known this for years but, sources said, it's done little to stop these weapons trafficking networks inside the United States, which move up to a million firearms across the border annually.

The latest disclosures are part of an inquiry launched by Grassley in October, which sought to uncover why the federal government canceled an interagency intelligence effort at the same time that it praised its success. 

Keep in mind that Mexico president Andrés Manuel López Obrador's administration is currently suing many major U.S. gun makers to the tune of $ 10 billion, blaming them for fueling cartel violence. The disclosures from whistleblowers indicate that the Biden administration itself is allowing the weapons trafficking to take place, or at least isn't doing much to stop it. 

Another curious twist is that Obrador has been the subject of at least two U.S.-based investigations into his own ties to the cartels; investigations that were also suddenly halted during the Obama and Biden administrations. According to ProPublica, the first investigation took place in 2010, and revolved around alleged cash payments from the cartels to Obrador's failed 2006 presidential campaign; information detailed by an Obrador staffer who was busted on drug charges by the DEA. 

To avoid federal prison, the operative gave a detailed account of the traffickers’ cash donations, which he said he helped deliver. He also surreptitiously recorded conversations with Nicolás Mollinedo Bastar, the close López Obrador aide who the operative said had participated in the scheme.

Along with the sworn statements of other witnesses, the taped conversations indicated that Mollinedo was aware of and involved in the donations by one of the country’s biggest drug mafias, current and former officials familiar with the case said.

According to ProPublica, the DEA wanted to mount a sting operation where they'd pose as drug traffickers and offer $5 million to Obrador's then-current campaign, but instead, the entire investigation was shut down by DOJ in 2011... right around the time that Operation Fast & Furious was starting to become front-page news. Another investigation was underway when Biden took office in early 2021, but according to the New York Times that too was shut down once Biden was in the White House.

Last month’s media reports, including one by ProPublica, about a U.S. inquiry into 2006 campaign donations — for an election he did not win — ignited a firestorm in Mexico. 

Mr. López Obrador publicly denounced the stories, implying they were aimed at influencing the country’s presidential election in June, in which his protégé, the former Mexico City mayor Claudia Sheinbaum, is leading the race to replace him. He suggested the reports could complicate talks on migration and fentanyl with the U.S. government, and said he considered not receiving President Biden’s homeland security adviser for a planned meeting in the Mexican capital. 

“How are we going to be sitting at the table talking about the fight against drugs if they, or one of their institutions, is leaking information and harming me?” Mr. López Obrador said at a regular news conference days after the stories published.

After President Biden called Mr. López Obrador, calming tensions, the Mexican foreign minister said that the U.S. homeland security adviser told Mexico “that this is a closed issue for them.” 

The Biden administration has handled Mr. López Obrador with great care, avoiding public criticism in favor of repeatedly dispatching top officials to Mexico City to meet with him and press for sustained migration enforcement in private. 

The decision to let the recent inquiry go dormant, the people familiar with it said, was caused in large part by the breakdown of a separate, highly contentious corruption case. In the closing months of the Trump administration in 2020, U.S. officials brought charges against Gen. Salvador Cienfuegos Zepeda, who served as Mexico’s defense secretary from 2012 to 2018.

While Democrats are blaming gun makers, Republicans, and Second Amendment advocates for enabling cartel violence, Grassley says that it's our own government that is failing to aggressively go after cartel traffickers. 

Last month, Grassley privately sent a letter to the U.S. ambassador to Mexico that provided evidence that the U.S. government has been aware that even firearms belonging to American armed forces were in the hands of Mexican narcos. The letter noted his investigation's "shocking finding … that the U.S. government had evidence of severe mishandling of U.S. resources to Mexico for some years. Yet, no corrective action appears to have been taken." In response, a State Department representative told Grassley they shared his concerns and offered to brief him about their progress "in the coming months."

Between Operation Fast & Furious, the sudden shutdown of Operation Thor, and the kid-glove handling of Obrador, I get the impression that the Obama and Biden administrations have done far more to fuel cartel violence south of the border than any other entity in the United States. Are they turning a blind eye to these trafficking efforts (or, in the case of Operation Fast & Furious, allowing guns to be trafficked) because it benefits their domestic gun control agenda, their foreign diplomacy with Obrador, or both? 

It's horrifying to realize that is a legitimate question to ask, but you don't have to be a crackpot conspiracy theorist to see something is terribly wrong here... and it's not our supposed lack of gun laws or our Second Amendment rights.