Only because the public frowns on congress dragging them out to the brick wall behind the building.If this country were run by the president or even run the way it was intended, they would have access to everything. Instead, we have sworn members of our government, military and ordinary citizens who sit in front of congress on a daily basis and refuse to answer their questions or flat out lie without consequence.
Everything we read in books about how the government runs is a charade and the President is far from the most powerful person in this country let alone the world.