You said "...no change of government in Pakistan has taken place without the American knowledge and support. "
This is purely speculative and your personal opinion. In this case atleast, Rice's repeated calls to Musharaff to shed his military uniform and restire civilian rule confirms Washington's unhappiness with imposition of emergency. You may recall that rediff and other newspapers reported that Musharaff was going to impose emergency and just then Washington brokered a power sharing between him and Bhutto.