Credit is not due to Bush for the Surge and COIN implementation. He had to be convinced of it, by many people, but namely Kagan and GEN Keane. Bush's plan for Iraq was to stick with Casey and "stay the course". Kagan and Keane's influence in Cheney's office got this ball rolling. It was AEI's plan that they were finally able to convince Bush to adopt. The JCS were firmly against troop increases, as was Bush, who kept repeating the he "takes advice from Generals on the ground", presumably Casey and Abizaid, who were both opposed to troop increases. Odierno comes in and gets on board as the future MNC-I commander, and then Petraeus.
Read "The Gamble" by Tom Ricks, who lays this all out quite nicely.
Also, watch this Charlie Rose interview with Ricks:
Charlie Rose & Tom Ricks - The Surge