Iran
After the Supreme Leader, the Constitution defines the President of Iran as the highest state authority. The President is elected by universal suffrage for a term of four years, however, the president is still required to gain the Leader's official approval before being sworn in before the Parliament (Majlis). The Leader also has the power to dismiss the elected president anytime. The President can only be re-elected for one term.
The President is responsible for the implementation of the constitution, and for the exercise of executive powers in implementing the decrees and general policies as outlined by the Supreme Leader, except for matters directly related to the Supreme Leader, who has the final say in all matters. Unlike the executive in other countries, the President of Iran does not have full control over anything, as these are ultimately under the control of the Supreme Leader. Chapter IX of the Constitution of the Islamic Republic of Iran sets forth the qualifications for presidential candidates. The procedures for presidential election and all other elections in Iran are outlined by the Supreme Leader. The President functions as the executive of affairs such as signing treaties and other international agreements, and administering national planning, budget, and state employment affairs, all as approved by the Supreme Leader.
Shia theocracy
Under the post-revolution Iranian constitution of 1979, Iran is government first and foremost by the Supreme Leader of Iran, who is responsible for the delineation and supervision of "the general policies of the Islamic Republic of Iran". The Supreme Leader is "Commander-in-Chief" of the armed forces, controls the military intelligence and security operations; and has sole power to declare war. The heads of the judiciary, state radio and television networks, the commanders of the police and military forces and six of the twelve members of the Council of Guardians are appointed by the Supreme Leader. The Assembly of Experts elects and dismisses the Supreme Leader on the basis of qualifications and popular esteem.  The Assembly of Experts is responsible for supervising the Supreme Leader in the performance of legal duties.