Secretary Gates, Adm. Mike Mullen and Secretary of State Clinton talk. Secretary of Defense Robert M. Gates, Chairman of the Joint Chiefs of Staff Adm. Mike Mullen and Secretary of State Hillary Clinton talk during a visit to Mexico City, Mexico, on March 23, 2010. Gates, Mullen and Clinton attended the Merida Initiative Plenary, which focuses on helping the Mexican government fight drug-trafficking cartels and other security threats. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 095359-T-EPA80-358.jpg Photo Gallery