First, there is the real Pakistan dependence on American military aid and technical and logistic support for their fleet of F-16's. They really cannot afford to get us really mad at them without the risk of that aid and support disappearing. OTOH, there is the political environment in Pakistan which certainly has a large pro-Taliban, pro-Al-Qaeda, anti-American element. This would lead one to speculate that the Pakistani's have given Bush an OK privately that they are politically unable to give him publicly. Until we actually see some real damage done to American forces by the Pakistani military that are confirmed by the U.S. I will subscribe to that theory.
But there is the wild card factor of Bush wanting to get Bin Laden before he leaves office. Could we just be seeing a personal vendetta combined with pretty good intelligence on the whereabouts of Bin Laden combining to yield a pull-out-the-stops effort to take down the Al-Qaeda leadership. And this with or without the OK from Pakistan. I would give this theory some credibility as well.
They should be enforcing their borders...
I cannot support our going into Paki. No reason to expand the war. I have supported Bush up to now. I want our troops home as soon as possible.
Pakistan operates less than 30 F-16s and is going to get another 30 odd. Meanwhile, it will be BUYING (not getting) almost 290 Chinese fighter aircraft. It can afford to do away with the F-16s other than to play around with the US taxpayer.