If the "mission" is to defeat the Taliban in Afghanistan, Gen. McChrystal is right and must be supported. If, however, one accepts that the Taliban cannot be militarily defeated, then the mission must be changed. The Taliban are a "social, cultural and political" entity - they are part of the fabric of Afghanistan, loathsome though they may be to Western sensibilities. When the Soviet Union was our enemy the Taliban were our allies - we armed, trained and financially supported them (ditto with Saddam Hussein).
MacArthur, Patton, McChrystal - all in my view were/are right and all were either fired, humiliated or rebuked. I admire Presidents Truman, Eisenhower and Obama, but in their dealings with these generals I think they were/are dead wrong. If the goal is victory, go with the generals; if compromise and half measures, go with the politicians.
As I concluded when I was in Vietnam, we clearly lacked the will to succeed and we deliberately confused North Vietnam Regulars with Viet Cong guerrillas. Today we deliberately confuse the Taliban with al Quaeda. No clear enemy = no clear mission. Using the military to defeat the Taliban is tantamount to using it to defeat the Republicans or Democrats -- ludicrous on its face. We need only look as far as our own "Posse Comitatus Act" for instruction -- anarchists and para-military extremists are dealt with by the FBI and other police agencies, not the 82nd Airborne.
At heart, the problem is our tortured use of the term "war" - as in "War on Poverty," "War on Drugs" and "War on Terror." Where there is no clear military mission, and where there is no clear mission, lives are sacrificed incrementally and senselessly as we stumble around looking for one - now curiously and infuriatingly because "we don't want those who have died to have done so in vain." (I watched firsthand while this specious reasoning culminated in 58,000 American deaths in Vietnam. I doubt whether the families of the first 1,000 dead feel better today that 57,000 more followed. I sure as hell don't.)
Social, ideological and criminal problems are the province of politicians, educators and the police. In the case of terror emanating from beyond our borders, the military may be needed to help establish and control a base of operations for specially trained police, intelligence agencies, special forces and black ops to do their jobs. We are lousy as occupiers and incompetent as nation-builders. Define the mission properly and the McChrystal "problem" will resolve itself. Until then, I'm with him!