In all of the McChrystal/Petraeus news, one thing is being forgotten: the commander of ISAF is a NATO position. When Obama and Gates fired General McKiernan and replaced him with McChrystal, a modest amount of due diligence was exerted to make the allies feel almost as if they are part of the process. This time, not so much. Of course, time was tight, and we will find out in the days ahead whether any allies were seriously consulted, but I doubt it. This is one of the many challenges that arise when folks where two or more hats--being responsible to two or more chains of command.
Speaking of command questions, another question: who runs CENTCOM now that Petraeus is moving down the chain of command to COMISAF? Few folks are asking about this. So far, two Marines have been mentioned--Petraeus's deputy at CENTCOM: LtG Allen; and General Matthis. Whoever runs CENTCOM is going to have an even more complicated hand to play with the biggest name in the military and previous occupant actually serving under him.