U.S. Presidential Debate and the issue of Pakistan

From Chris Usatuck:

Friday night was the first of three presidential debates and was focused on national security and foreign policy. The most interesting exchange in the night came when the discussion turned to Pakistan and what to do about terrorists who cross the western border into Afghanistan to fight U.S. forces.

In the debate, Sen. Obama stated that he would launch military strikes against terrorists in Pakistan if the Pakistani government refused to act. McCain countered with,"You don't say that out loud..." which is basically saying that he agrees with Obama but that such a mission should be done in secrecy. This is the same policy that the Bush administration has been persuing since July.

Now I'm all for rooting out Taliban and Al-Qeada terrorists who have had a safe haven in Western Pakistan but I wonder what legal authority the U.S. has in crossing into Pakistan without the approval of the government.