Congress is the source of “all legislative powers” with the authority “to make all laws” while the president is vested with the authority to “take care that the laws be faithfully executed.” But the transition from the creation of law to the execution of law is not seamless. Through its legislative power, Congress is able to direct and limit the president's authority in the execution of law. Yet presidents are able to exercise discretion over the implementation and interpretation of law through their control of the executive branch. The transition from creation to execution is a continued source of controversy between the branches and at the center of the controversy is the question of whether the need for discretion should overshadow Congress’ delegation of authority.