|Systems of government|
Countries in which constitutional provisions for government have been suspended (e.g. military dictatorship
Countries which do not fit any of the above systems (e.g. transitional governments, unclear political situations or no government)
A presidential system is a democratic and republican system of government where a head of government leads an executive branch that is separate from the legislative branch. This head of government is in most cases also the head of state, which is called president.
In presidential countries, the executive is elected and is not responsible to the legislature, which cannot in normal circumstances dismiss it. Such dismissal is possible, however, in uncommon cases, often through impeachment.
The title "president" has persisted from a time when such person personally presided over the governing body, as with the President of the Continental Congress in the early United States, prior to the executive function being split into a separate branch of government.
A presidential system contrasts with a parliamentary system, where the head of government is elected to power through the legislative. There is also a hybrid system called semi-presidentialism.
Countries that feature a presidential or semi-presidential system of government are not the exclusive users of the title of president. Heads of state of parliamentary republics, largely ceremonial in most cases, are called presidents. Dictators or leaders of one-party states, popularly elected or not, are also often called presidents.
Presidentialism is the dominant form of government in the continental Americas, with 19 of its 23 sovereign states being presidential republics. It is also prevalent in Central and southern West Africa and in Central Asia.