I get the sense that Gen. McChrystal is not unlike Gen. George Patton, of World War II fame. Patton was a public relations disaster but a hell of a battlefield soldier. McChrystal seems to be the same.
Leaders like Patton and McChrystal need to function at the tactical level while not being given access to the strategic level. That is, they need to work for generals who have, and are willing to use, political skills much as Patton worked for Eisenhower.
Meanwhile, this article by The Washington Post's Dana Milbank arrives at the same conclusion via a slightly different route. Milbank is more interested in politics and less interested in history than Cohen.