Six times in the course of five pages, the report's authors note that, unless Pakistan does a better job of controlling its borders—the western tribal areas, where Taliban leaders find safe haven and move reinforcements and supplies into Afghanistan and back again—the U.S. military successes of recent months are for naught.
For instance, on Page 1, the report defines "our ultimate end state" as "the eventual strategic defeat of al-Qaida in the region," but it adds that this "will require the sustained denial of the group's safe haven in the tribal areas of western Pakistan."
On Page 3: The "denial of extremist safe havens will require greater cooperation with Pakistan along the border with Afghanistan."
On Page 5: "Consolidating those gains [made in the fight against the Afghan Taliban] will require that we make more progress with Pakistan to eliminate sanctuaries for violent extremist networks."
Those italics (all mine) make the point: Clearing the safe havens in Pakistan is not just an important ingredient in achieving our strategic objectives in Afghanistan; it is a requirement. Without it, all other successes are merely tactical and, even then, probably short-lived ("fragile and reversible," as the report puts it).