Every nation has a head of state, which serves as the chief public representative for the country. Depending on the constitution, the head of state may or may not exercise executive power.
In parliamentary systems found across the world, and especially in Europe, the prime minister, or premier, functions as the chief executive officer and answers to the parliament. Authority is vested in cabinets responsible to the parliament. The prime minister is the head of the cabinet, and therefore the chief executive of the nation.
In such systems, the prime minister also answers to a ceremonial head of state. In some nations it is a weak president and in constitutional monarchies, such as the United Kingdom or Spain, it is the hereditary monarch.
Unlike with parliamentary forms of government, the President of the United States is vested with real authority and there is no prime minister. The US President is both the head of state and chief executive. Versions of the American presidential system have been adopted in Latin America and the developing world.
And finally, France offers a third example of executive power distribution. In 1958, Charles de Gaulle created the Fifth Republic, which gave France's president potent executive powers. The president has the power to dissolve the national legislature and call national referenda. He or she also appoints the prime minister, who must have the support of a majority in France's lower house. Post-communist countries, including Russia, modeled their constitutions after France. Thus, Russian President Putin will have the opportunity to seek the next best office as Russia's Prime Minister.