The modern presidency is always too powerful and yet is always inadequate. Rather it created a government of seperate institutions with shared powers.
Presidential power is inherently weak.
Just because the person sitting in the White House is the President, does not mean that people who also possess power and authority will do as he wishes. It is influence. Presidents differ in terms of their ability to influence the conduct of the men who make up government. Influence then becomes the mark of leadership. According to Neustadt, the power of the president is the power to persuade.