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... (GunPolicy.org)