Keep in mind that McChrystal is not the strategic commander here. In both roles (as ISAF commander and commander of US forces - most of them anyway - in Afghanistan) he is an operational commander responsible for designing and carrying out a campaign that will reach strategic goals set by others. This means that he is constrained and restrained in what he can do. Yes, he has quite a bit of influence on what will happen, but the strategy is formulated in various American and European capitols, Brussels, and Tampa.