<P> 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 . </P> <P> In a full - fledged presidential system, a politician is chosen directly by the people or indirectly by the winning party to be the head of government . Except for Belarus and Kazakhstan, this head of government is also the head of state, and is therefore called president . The post of prime minister (also called premier) may also exist in a presidential system, but unlike in semi-presidential or parliamentary systems, the prime minister answers to the president and not to the legislature . </P> <P> The following characteristics apply generally for the numerous presidential governments across the world: </P> <Ul> <Li> The executive can veto legislative acts and, in turn, a supermajority of lawmakers may override the veto . The veto is generally derived from the British tradition of royal assent in which an act of parliament can only be enacted with the assent of the monarch . </Li> <Li> The president has a fixed term of office . Elections are held at regular times and cannot be triggered by a vote of confidence or other parliamentary procedures, although in some countries there is an exception which provides for the removal of a president who is found to have broken a law . </Li> <Li> The executive branch is unipersonal . Members of the cabinet serve at the pleasure of the president and must carry out the policies of the executive and legislative branches . Cabinet ministers or executive departmental chiefs are not members of the legislature . However, presidential systems often need legislative approval of executive nominations to the cabinet, judiciary, and various lower governmental posts . A president generally can direct members of the cabinet, military, or any officer or employee of the executive branch, but cannot direct or dismiss judges . </Li> <Li> The president can often pardon or commute sentences of convicted criminals . </Li> </Ul>

Advantages and disadvantages of presidential form of government