Now, if our job is done, we ought to leave. But if our job is not done, we should stay. A strong president might look at the situation and simply say, "We're not leaving." That would absolutely work, with a strong president. Obama is not strong. He's pulling out everywhere because someone suggested it. He's retreating on all fronts.
While the Pakis have never been reall allies, at least Bush kept them from being overtly against us (I believe he made it clear they could either "join" us or suffer more direct actions to ensure they wouldn't actively interfere). During his campaign, Obama lit the fuse by saying that Pakistan need to be dealt with more than Afghanistan and Iraq - this eviction is a direct result of his ineptitude.