CIUDAD JUÁREZ, Mexico — The killing of an American consulate worker and her husband over the weekend in the shadow of the bridge that links this ramshackle city with the United States has become a public symbol of the mounting concern here that President Felipe Calderón’s strategy for attacking Mexico’s drug cartels is veering far off course.

The city braced for a visit on Tuesday from Mr. Calderón, who has been forced by the relentless violence here to recalibrate his approach and acknowledge that merely concentrating firepower on the drug gangs is not working.

In an about-face, the Mexican government has begun refocusing much of its energy on attacking social issues in Ciudad Juárez, in what officials say privately could be an experiment for other Mexican cities that are consumed by drug violence.

American officials say they have encouraged and supported the new approach, pointing to the lack of opportunity here.