There are two main forms of democratic government: the presidential system and the parliamentary system. In a presidential system, the head of state and head of government are the same person and there is a separation of powers between the executive and legislature. Key features include fixed terms for the president and independence from the legislature. Parliamentary systems have the legislature as the supreme governing body, with the executive deriving power from and being accountable to the legislature. Key features include collective cabinet responsibility and the potential for more frequent changes of government. The document compares some merits and demerits of each system.