Read this: Kerry "has emerged in the past few years as an important envoy for Afghanistan and Pakistan during times of crisis," a Washington Post report stated in May 2011, as Kerry undertook another trip to the two countries. The killing of Osama bin Laden "has generated perhaps the most important crossroads yet," the report continued, as the senator spoke at a press conference and prepared to fly from Kabul to Pakistan. Among matters discussed during the May visit to Pakistan, under the general rubric of "recalibrating" the bilateral relationship, Kerry sought and retrieved from the Pakistanis the tail-section of the U.S. helicopter which had had to be abandoned at Abbottabad during the bin Laden strike. In 2013, Kerry met with Pakistan's army chief Gen. Ashfaq Parvez Kayani to discuss the peace process with the Taliban in Afghanistan.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): Who did the Washington Post say Kerry was an envoy for?
Afghanistan and Pakistan