In the United States, Article II of the Constitution provides for the office of the presidency, which is held for four-year terms and filled by election through the electoral college. The president is given full responsibility for the execution of the laws and is therefore the head of all executive agencies. With the consent of Congress he appoints cabinet members and any other executive officials he sees fit.
As commander in chief of armed forces the president has control over the military, although Congress tried to limit his war-making power with the War Powers Act of 1973. He is also responsible for the conduct of foreign affairs, although his treaties and appointments must be approved by the Senate and his expenditures by the House of Representatives.
To be eligible for the presidency one must be a native-born citizen, over 35 years old, and at least 14 years resident in the United States. The Twenty-second Amendment (1951) limits a president to two four-year terms.