U.S. Attorney General Eric H. Holder Jr. may show up on “Jeopardy!” one of these days. No, not as a contestant — as an answer. The clue: “He’s the first attorney general in U.S. history to be held in contempt of Congress.” The answer: “Who is Eric Holder?”

That’s surely not the distinction Mr. Holder was seeking when he took the job. But thanks to the scandal known as Operation Fast and Furious, that’s what he’s best known for: overseeing an operation that put more than 2,000 guns into the hands of a Mexican drug cartel and led to the deaths of hundreds of Mexican citizens and a U.S. Border Patrol agent.

Presumably, this appalling mortality rate wasn’t the intention when Fast and Furious was launched in 2009. But we all know what paves the road to hell.

How did it get to this point? Let’s review the basic facts.

The idea was that agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) would let U.S.-based “straw purchasers” associated with the Sinaloa drug cartel buy guns from federally licensed gun dealers and allow them to “walk” across the border into Mexico (whose government wasn’t informed). The agency would track the weapons and trace them to high-level cartel operatives.

It doesn’t take a degree in law enforcement to see that the “track and trace” portion of the forgoing description probably is its key detail. According to whistleblowers, this simply wasn’t done. Once the guns walked across the border, their whereabouts became a mystery to the ATF. Then the weapons began showing up at crime scenes.

Mario Gonzalez Rodriguez was at one of them. The brother of a former Mexican state attorney general, Rodriguez turned up in a shallow grave on Oct. 21, 2010 — the victim of torture. Two Fast and Furious guns were found in the possession of his kidnappers following a shootout with Mexican police.

Less than two months later, Border Patrol Agent Brian A. Terry was at another of those crime scenes. The 40-year-old former Marine was fatally shot during a firefight. Once again, two of the weapons recovered afterward were discovered to be Fast and Furious firearms.

Shortly after Terry’s death, ATF agents, troubled by the way the operation was spiraling out of control, told Sen. Chuck Grassley, Iowa Republican, about Fast and Furious. They hoped Mr. Grassley, ranking member of the Senate Judiciary Committee, could put a stop to it.

To do that, Mr. Grassley needed information. That’s when Fast and Furious moved from tragedy to scandal: President Obama’s Justice Department, under the watchful eye of Mr. Holder, decided not to cooperate, but to cover up.

Any claim “that ATF ‘sanctioned’ or otherwise knowingly allowed the sale of assault weapons to a straw purchaser who then transported them to Mexico, is false,” Assistant Attorney General Ronald Weich wrote to Mr. Grassley on Feb. 4, 2011. “ATF makes every effort to interdict weapons that have been purchased illegally and prevent their transportation into Mexico.”

Not every effort, it seems. Nine months later, after weeks of stonewalling and attempts to find “dirt” on the whistleblowers, Justice Department officials finally came clean. On Nov. 8, 2011, Mr. Holder admitted under oath that gun-walking had, in fact, occurred. The Feb. 4 denial was rescinded.

But it’s not over yet. According to the Justice Department, there are approximately 140,000 pages of Fast and Furious-related documents. How many have officials turned over to Rep. Darrell E. Issa, chairman of the House Oversight Committee? About 7,600, and many were so heavily redacted as to be practically useless.

The administration continues to drag its feet, including a June 28 declaration by Mr. Obama that many of the documents were shielded by executive privilege.

Small wonder Congress wants answers. The administration has no business engaging in such a shameful and outrageous cover-up. Congress should continue to make every effort to get to the bottom of this reckless and irresponsible operation — and take immediate steps to ensure that it never happens again.

When Mr. Obama took office, he vowed that his administration would be “the most open and transparent in history.” For the sake of those who died because of Fast and Furious, let’s hope he remembers — and honors — that promise.

Ed Feulner is president of the Heritage Foundation (heritage.org).