Petraeus is not simply another McChrystal. While McChrystal implemented COIN doctrine, mixing in his obsession with "kinetic operations" by US Special Forces, Petraeus literally wrote the book - namely, The US Army/Marine Corps Counter-insurgency Field Manual.
If the COIN cult has a guru (whom all obey unquestioningly), it's Petraeus. The aura that surrounds him, especially among the chattering classes of the Washington punditocracy, is palpable, and he has a vast well of support among Republicans and assorted right-wingers on Capitol Hill, including the Holy Trinity: John McCain, Lindsay Graham and Joe Lieberman.
Not surprisingly, there have been frequent mentions of Petraeus as a candidate for the GOP nomination for president in 2012, although Obama's deft selection of Petraeus seems, once and for all, to have ruled out that option, since the general will be very busy on the other side of the globe for quite a while.
Even before the announcement that Petraeus had the job, the right's mighty Wurlitzer had begun to blast out its critique of the supposedly pernicious effects of the July deadline. The Heritage Foundation, in an official statement, proclaimed: "The artificial Afghanistan withdrawal deadline has obviously caused some of our military leaders to question our strategy in Afghanistan ... We don't need an artificial timeline for withdrawal. We need a strategy for victory."