The executive is the part of the government that has sole authority and responsibility for the daily administration of the state. The executive branch executes, or enforces the law. The division of power into separate branches of government is central to the idea of the separation of powers. The separation of powers system is designed to distribute authority among several branches — an attempt to preserve individual liberty in response to tyrannical leadership throughout history. The executive officer is not supposed to make laws (the role of the legislature) or interpret them (the role of the judiciary). The role of the executive is to enforce the law as written by the legislature and interpreted by the judicial system. The executive can be the source of certain types of law, including decree or executive order. Executive bureaucracies are commonly the source of regulations. In this context, the executive branch of government consists of leader(s) of an office or multiple offices. Specifically, the top leadership roles of the executive branch may include: head of state—often the de jure leader, the president, the chief public representative and living symbol of national unity. head of government—often the de facto leader, prime minister, overseeing the administration of all affairs of state. defence minister—overseeing the armed forces, determining military policy and managing external safety. interior minister—overseeing the police forces, enforcing the law and managing internal safety. foreign minister—overseeing the diplomatic service, determining foreign policy and managing foreign relations. finance minister—overseeing the treasury, determining fiscal policy and managing national budget. justice minister—overseeing criminal prosecutions, corrections, enforcement of court orders. In a presidential system the leader of the executive branch is both the head of state and head of government. In a parliamentary system, a cabinet minister responsible to the legislature is the head of government, while the head of state is usually a largely ceremonial monarch or president. In the United States, this branch of the government is controlled by the President and his/her cabinet.