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. The essense of a president's persuasive task with congressmen and everybody else, is to induce them to believe that what he wants of them is what their own appraisal of their own responsibilities requires them to do in their interest, not his. The power to persuade amounts to bargaining. Presidential popularity 1 and 2. For instance, a presidential veto represents a presidents failure to persuade members of congress to pass a bill he wants.