Obama visits Mexico

MEXICO CITY. Confronting a security threat on America's doorstep, President Barack Obama launched a swift diplomatic mission to Mexico Thursday to show solidarity with a troubled neighbor — and to prove that the US is serious about halting the deadly flow of drugs and weapons. Administration officials also said Obama would push for Senate ratification of a Latin American arms trafficking treaty, an announcement he would make in Mexico. It was adopted by the Organization of American States and signed by former President Bill Clinton but never ratified by the Senate. The treaty would curb guns and ammunition trafficking that threatens regional security, and show the US is serious about confronting a security threat on its doorstep.