Why Does the United States Continue to Support Pakistan?

Since 1947 the US has supported Pakistan. For decades the US taxpayer have sent billions of dollars to Pakistan. Maybe it is time to ask ourselves, just what have we benefited from our efforts. In this age of Jihad and the radical Islamic conflicts that have engulfed the world, it is time to assess who is an ally and who is not.
Pakistan is home to one of the largest populations of Muslims. Pakistan is also a nuclear state, the only predominantly Muslim nation to hold that status. Pakistan seems to be more interested in courting our enemies than the US who so generously supports them with aid. Pakistan sold its technology to the worst promoters of terrorism on the planet through black market deals. They support the Haqqani network, a group of extremists fighting directly against the interests of the US. Pakistan harbored and protected Osama bin Laden for years while publicly denying any knowledge of his whereabouts. He lived only a few miles from Pakistan's premier Military Academy. Pakistan promotes and strongly imposes Sharia Law and persecutes Pakistani Christians. They are working directly with Iran and North Korea on trade and weapons, particularly nuclear weapons.
So why are they considered an ally and why are we still supporting them? That is a question we must answer.