A parliamentary system is a form of government based on the fusion of powers. In this system the head of government derives their democratic legitimacy from their ability to command the support ("confidence") of a majority of the parliament, to which they are held accountable. This head of government is usually, but not always, distinct from a ceremonial head of state. This is in contrast to a presidential or assembly-independent system, which features a president whose power is balanced against the legislature and the judiciary, and cannot be replaced by a simple majority vote.