US National Intelligence Director– John Negroponte resigned and became Deputy Secretary of State.[51] Retired Admiral John M. McConnell took his place. CENTCOM commander– Navy Admiral William J. Fallon replaced General John Abizaid as CENTCOM commander Commander of Multinational Force Iraq – counter-insurgency expert General David Petraeus replaced General George Casey as Commander of Multinational Force Iraq. Archived July 8, 2007, at the Wayback Machine</ref> US Ambassador to Iraq and ambassador to the United Nations – Bush announced the appointment of US diplomat Ryan C. Crocker as the new ambassador to Iraq.