Something happened in the background
The Pakistani nation is split, and the Taliban/Al-Q have lots popular and even governing elite support. (Remember, this is the country that only slapped the wrist of the rogue nuke scientist who sold their bomb secrets, a hanging offense anywhere else.). In the past, the Pakistanis have not been very serious about going after these guys, so this sudden turn-around tells me someone is applying a lot of pressure behind the scenes.
War with the Taliban and support for the US is domestically a very risky policy for the government, so the alternatives must be intolerable. We're seeing a game of hardball being played here.