Last week was a very bad period for America’s drug warriors. The scandal surrounding Operation Fast and Furious deepened. This was the ill-fated scheme by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) to allow illegal guns to be smuggled from the United States into Mexico so U.S. authorities could track how the drug cartels obtained and dispersed their weaponry. That scandal had been building since December 2010, when several of the weapons were found at the scene of a firefight between cartel gunmen and the U.S. Border Patrol in Arizona’s Peck Canyon (near Nogales) that left Border Patrol agent Brian Terry dead. Information soon emerged that at least two thousand weapons had leaked south into Mexico under Operation Fast and Furious. And the ATF had lost track of many of them. The firearms have now been linked to nearly two hundred murders in Mexico.

Congressional Republicans and other Obama-administration critics have focused on the issue and uncovered evidence that the ATF, the U.S. attorney’s office in Phoenix and perhaps even the Justice Department in Washington may have tried to orchestrate a cover-up of that fiasco. Matters came to a head when Attorney General Eric Holder found himself on the hot seat in hearings before an often hostile House Judiciary Committee on December 8.

If revelations about Operation Fast and Furious were not embarrassing enough for the drug-war bureaucracy, the New York Times broke a story on December 3 describing how Drug Enforcement Administration agents and other law-enforcement personnel engaged in a money-laundering operation as part of an investigation of the Mexican drug cartels. Agents facilitated the passage of shipments of hundreds of thousands of dollars across the U.S.-Mexico border and in some cases even made deposits in accounts that the traffickers had designated. The rationale for that operation was similar to that of Operation Fast and Furious. U.S. authorities believed that they would be able to track the funds and identify how the cartels move their money, the personnel involved in the money laundering, and where the organizations keep and conceal their cleansed assets. It isn’t clear whether the monitoring of the money-laundering program was any more effective than the monitoring of weapons.

Those episodes suggest that there is a fine line between creative law-enforcement schemes and having U.S. authorities do the dirty work of—and become useful idiots for—criminal organizations. Operation Fast and Furious clearly drifted over that line, and events may show that the money-laundering investigation has done the same.

But that is not the most troubling aspect of the two episodes. Indications of a possible cover-up in the Fast and Furious scandal are much more serious—especially if high-level officials of the Justice Department were involved. Another very troubling element emerged at the House hearings. Democratic members of the Judiciary Committee tried to deflect criticism of Holder, and even the failed gun-tracking program, by trying to turn the hearings into a platform for touting an alleged need for tighter U.S. gun laws.

That strategy wasn’t simply a cynical smokescreen to divert attention from the Fast and Furious debacle. It also was the continuation of a long-time effort by both the Obama administration and the Mexican government to use allegedly lax U.S. gun laws as a scapegoat for the soaring drug-related violence in Mexico. The notion that tighter U.S. gun laws would inhibit the drug cartels and significantly reduce the number of killings in Mexico is nonsense. Not only have the cartels obtained some of their weapons from military arsenals in Central America (and at least in a few cases from armories in Mexico itself), but also there are extensive black and grey markets in weaponry all over the world. Organizations that make their livelihood operating in a black market in illegal drugs—and have an estimated $35 billion to $60 billion in annual revenues at their disposal—would have little trouble obtaining all the weapons they desire regardless of U.S. gun laws. The argument that shutting down gun stores and gun shows in Arizona, Texas and other southwestern states would be a cure for Mexico’s tragic, drug-related carnage is either naïve or terribly cynical.

Trotting out such a scapegoat merely distracts us from confronting the reality that the violence in Mexico results from vicious turf fights over control of the supply routes to the lucrative consumer market in illegal drugs in the United States. And that market is so lucrative primarily because of a huge black-market premium (often 90 percent of the retail price) caused by a prohibitionist policy. The problem of drug-related violence in Mexico will not be alleviated until the United States—as the largest consumer of illegal drugs—abandons the failed prohibition model.

In the meantime, U.S. authorities should at least not actively assist the cartels by engaging in Keystone Kops programs like Operation Fast and Furious. Investigations regarding that episode and the just-revealed money-laundering scheme should be conducted with maximum diligence.

Ted Galen Carpenter, senior fellow for defense and foreign policy studies at the Cato Institute, is the author of eight books on international affairs, including Bad Neighbor Policy: Washington's Futile War on Drugs in Latin America. He is also a contributing editor to The National Interest.