President Barack Obama and Mexico's President Enrique Pena Nieto, right, leave a joint news conference in Mexico City, Mexico, Thursday, May 2, 2013. Obama sought on Thursday to tamp do

 

              President Barack Obama and Mexico
President Barack Obama and Mexico's President Enrique Pena Nieto, right, leave a joint news conference in Mexico City, Mexico, Thursday, May 2, 2013. Obama sought on Thursday to tamp down a potential rift with Mexico over a dramatic shift in the cross-border fight against drug trafficking and organized crime, acceding that Mexicans had the right to determine how best to tackle the violence that has plagued their country. (AP Photo/Dario Lopez-Mills)