Presidential system

A presidential, strong-president, or single-executive system (sometimes also congressional system) is a form of government in which a head of government (usually titled "president") heads an executive branch that derives its authority and legitimacy from a source that is separate from the legislative branch. The system was popularized by its inclusion in the Constitution of the United States. This head of government is often also the head of state. In a presidential system, the head of government is directly or indirectly elected by a group of citizens and is not responsible to the legislature, and the legislature cannot dismiss the president during their term in office except in extraordinary cases. A presidential system contrasts with a parliamentary system, where the head of government (usually called a prime minister) derives their power from the confidence of an elected legislature, which can dismiss the prime minister with an ordinary majority. However, dictators or leaders of one-party states, whether popularly elected or not, often carry the title of president.