From the Washington Post:
When Defense Secretary Robert M. Gates called Petraeus in early 2007 to offer him command of coalition forces in Iraq, he also posed another question: What did Petraeus think ofAdm. William J. “Fox” Fallon as head of Central Command, overseeing U.S. military operations throughout the Middle East and Afghanistan?
It was an exchange Petraeus would remember ruefully. Over the months that followed, Fallon and Petraeus clashed over resources, strategy and how quickly to reduce the number of troops in Iraq.
Although new to the Middle East and inexperienced in ground warfare, Fallon was one of the most senior officers in the U.S. military and one of the few Vietnam War veterans still on active duty. Petraeus, by contrast, was one of the first members of the military's post-Vietnam generation, becoming a platoon leader in May 1975, days after the last Marine helicopter left Saigon.
As Centcom commander, Fallon was technically Petraeus’s new boss. In practice, however, Petraeus bypassed the chain of command and answered directly to Bush, enjoying what was probably the most direct relationship between a frontline general and his commander in chief since the Civil War…