The Senate voted Tuesday to effectively block the Justice Department from undertaking gun-smuggling probes like the flawed "Operation Fast and Furious" aimed at breaking up networks running guns to Mexican drug cartels but that lost track of hundreds of the weapons, some of which were used to commit crimes in Mexico and the United States.
The 99-0 vote would block the government from transferring guns to drug cartels unless federal agents "continuously monitor or control" the weapons. The amendment's sponsor, Sen. John Cornyn, R-Texas, called the vote "just the first step towards ensuring that such a foolish operation can never be repeated by our own law enforcement."
The Justice Department has already stopped the program.
A Justice Department official, who spoke on condition of anonymity because Congress did not ask the department for its views, said the amendment essentially reflects DOJ policy.
In an interview Tuesday with ABC News, President Barack Obama said "we will find out who and what happened in this situation and make sure it gets corrected."
The vote came as the Senate debated a $128 billion spending measure that would fund Justice Department operations and those of several other Cabinet agencies for the 2012 budget year already under way.
Operation Fast and Furious was a gun-smuggling investigation by the Bureau of Alcohol, Tobacco, Firearms and Explosives aimed at tracking small-time illicit gun buyers up the chain to major traffickers in an effort to take down arms networks. In the process, ATF agents lost track of many of the weapons.
Fast and Furious came to light after two assault rifles purchased by a now-indicted small-time buyer under scrutiny in the operation turned up at a shootout in Arizona where Customs and Border Protection agent Brian Terry was killed.
The operation has caused something of a firestorm in Washington and is the focus of an investigation by House Republicans, who have questioned whether Attorney General Eric Holder has been candid about all he knows about the botched operation.
Holder already has called a halt to the practice of allowing guns to "walk" in an effort to track them to arms traffickers, saying in a recent letter to lawmakers that "those tactics should never again be adopted in any investigation."
The operation was designed to respond to criticism that the agency had focused on small-time gun arrests while major traffickers had eluded prosecution.
As recently as 11 months ago, the Justice Department's inspector general criticized ATF for focusing "largely on inspections of gun dealers and investigations of straw purchasers, rather than on higher-level traffickers, smugglers and the ultimate recipients of the trafficked guns."
The IG said some ATF managers discourage agents from conducting complex conspiracy investigations that target high-level traffickers.
Associated Press writer Pete Yost contributed to this report.