The administration offers a modest plan to stem gun flow to Mexico

Tuesday, December 28, 2010; 7:15 PM

THE OBAMA administration has shied away from issues involving the regulation of guns. Now comes word from The Post's James V. Grimaldi and Sari Horwitz that the Justice Department is advancing a plan to stem the flow of semiautomatic rifles to violence-plagued Mexico. It's about time.

Over the past three years, some 30,000 people have been gunned down in Mexico in attacks fueled by drug cartels. Military and law enforcement officers there have seized some 60,000 weapons that were used in these crimes and traced to the United States. Mexican President Felipe Calderon has pleaded with U.S. officials to step up enforcement of gun laws and reinstate the assault-weapons ban. Doing so would be good policy but would trigger a fierce fight. For the moment, the administration has something much more modest in mind.

As The Post reports, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) plans to require some 8,500 gun dealers along the Southwest border to alert the agency when they sell "within five consecutive business days two or more semiautomatic rifles greater than 0.22 caliber with detachable magazines" to the same individual. The administration will notify dealers about this requirement through "demand letters," which were created in 2000 largely to extract information from dealers who were not complying fully with federal reporting rules. The ATF program would lapse after six months unless other action is taken.

Mayors Against Illegal Guns last year urged the use of demand letters but only for dealers who have sold a significant number of weapons traced to crimes. That plan would be worth considering if the ATF proposal proves unworkable.

When reports of its plan surfaced, the administration came under immediate attack from the gun rights lobby. The National Shooting Sports Foundation, the firearms industry trade association, argued that the administration lacked the legal authority to demand data on rifles and shotguns. It has a point: While Congress authorized the ATF to collect information on handgun sales, it declined to extend the requirement to long guns. A court is likely to be asked to decide whether demand letters may be used to shake loose this information.

Regardless of the outcome, the administration should continue to look for lawful ways to dam the current of illegal guns, particularly those that are helping to destabilize America's neighbor to the south.

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