From his command in Iraq, Petraeus returned to Fort Leavenworth, Kansas. There, from 2005 to 2007, he and his staff rewrote the Army Counterinsurgency Field Manual, the first major revision of the text since Vietnam. Counterinsurgency strategy (COIN) proposes that the military wage its wars through engaging with local populations and promoting their sense of security over efforts that alienate local groups, even if these tactics are successful at eliminating insurgents. For such a strategy to work, though, it would require closer relations between troops and Iraqis in places where the United States had tried to maintain a light footprint. COIN took off, quickly rallying a passionate collection of advocates -- their detractors would label them COINdinistas -- eager for a change of strategy in the struggling war in Iraq. That change was put into effect with the surge, the deployment of an additional 20,000 troops to Iraq announced in January 2007, and on Feb. 10, 2007, Petreaus took command of U.S. forces in Iraq to guide the new effort.
Here, Petraeus assumes command from CENTCOM commander Gen. John Abizaid in Baghdad, Iraq, replacing Gen. George Casey. He had recently been promoted to the rank of four-star general.