At least 17 people -- including three young students -- were killed due to drug prohibition violence in northern Mexico this weekend.

Homeland Security Secretary Janet Napolitano issued her now famous warning to drug trafficking organizations, saying: "Don't even think about bringing your violence and tactics across this border. You will be met by an overwhelming response." Dave Gibson opines that prohibition-created drug trafficking organizations have already been bringing their tactics across the border. For instance, seven months ago, Nogales, Arizona Police Chief Jeff Kirkham announced that his department had been warned by a Mexican drug traffickers that his officers would be targeted for murder if they carry out another off-duty drug bust. Chief Kirkham said, "The warning was...that the officers, if they are off duty, are to look the other way and ignore any drug trafficking loads that are coming across the border, otherwise they will be targeted."

A series of high-profile murders of U.S. citizens along the border with Mexico has raised fears about drug prohibition violence spilling over into the United States.

Suspected drug trafficking organization gunmen hurled grenades, burned vehicles and blocked streets in a rapid series of attacks in Mexico's second-largest city. The seven attacks within two hours appear to have been coordinated. A policeman and two transportation workers were injured in the attacks.