Adm. Mike Mullen joined Secretary Gates in a Pentagon press conference. Chairman of the Joint Chiefs of Staff Adm. Mike Mullen joined Secretary of Defense Robert M. Gates in a Pentagon press conference to discuss the resignation of Gen. Stanley A. McChrystal on June 24, 2010. McChrystal had been the senior commander of U.S. and NATO forces in Afghanistan. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 693723-P-UZA69-144.jpg Photo Gallery