U.S. Attorney General Eric Holder testified before Congress Tuesday about a botched arms trafficking operation and allegations of deceit and coverup.

The venue was the U.S. Senate Judiciary Committee and Holder almost immediately appeared to plead that "Operation Fast and Furious" be put into larger context.

"This operation was flawed in its concept and flawed in its execution, and unfortunately we feel the effect for years to come as guns that were lost during this operation continue to show up at crime scenes both here and in Mexico," he said. "This should never have happened and it must never happen again."

But Holder added: "The mistakes of Operation Fast and Furious, serious though they were, should not deter or distract us from our critical mission to disrupt the dangerous flow of firearms along our southwest border."

The United States, he said, was "losing the battle" to stop gun trafficking to Mexico and must act, "but beyond identifying where errors occurred (in Fast and Furious) and ensuring they never occur again, we must be careful not to lose sight of the critical problem …"

The problem, however, isn't just the smuggling of weapons to Mexico's drug cartels and some of those weapons finding their way back to U.S. soil, where some have been used in crimes. As serious as those problems are, there is also the problem of law enforcement officials acting in accordance with the laws.

"Let me be clear, the bottom line is that it doesn't matter how many laws we pass if those responsible for enforcing them refuse to do their duty as was in the case of Fast and Furious," U.S. Sen. Charles Grassley, R-Iowa, told Holder.

Operation Fast and Furious was launched by the Bureau of Alcohol, Tobacco, Firearms and Explosives in 2009 to track smuggled firearms to Mexican drug cartels. Gun dealers along the Mexican border were allowed to sell the firearms to straw buyers to enable the ATF to track the weapons and those who possessed them.

The problem was that the ATF failed to do so. U.S. Border Patrol officers were also ordered not to stop the traffickers. As many as 2,000 weapons sold in the operation are missing.

The venture came to an end in late 2010 when a Border Patrol officer was killed in an ambush and one of the trafficked weapons was found near his body. Disgruntled ATF agents blew the whistle on the program many had opposed from the outset.

Grassley recounted Tuesday a letter from the U.S. Justice Department over whistle-blower allegations. The letter said the "ATF makes every effort to interdict weapons that have been purchased illegally and prevent their transportation to Mexico."

"In the nine months since then, mounting evidence has put the lie to that claim, documents contradicting the denials have come to light," Grassley said. "Then six ATF agents testified powerfully at dual house oversight hearings. They confirmed that gun walking occurred in Fast and Furious.

"Just last week Assistant Attorney General Lanny Breuer admitted in this room that the department's letters to me in February were false" and he "admitted he knew all along it was false."

In addition to officials of the Justice Department, which is in charge of ATF and the Border Patrol, and ATF management, Holder himself has come under suspicion. In testimony earlier this year he indicated he only learned the Fast and Furious a few weeks previously but documents indicated he knew had been briefed on the operation much earlier.

On Tuesday, he said he misspoke.

Holder's explanations, however, aren't likely to put the matter to rest. Fast and Furious is likely to become slow and painful for the administration of U.S. President Barak Obama as elections roll closer and the obvious ineptitude, plus illegalities of the operation, possibly make their way into the political debate.