Chief executive

A chief executive of a nation-state is the leader of the nation. He or she makes or proposes laws, makes decrees, and appoints officials. He or she wields various powers.
==In Republics and Parliamentary Democracies==
A president is chief executive of a republic. He wields powers to propose legislation, appoint officials, and command the armed forces. He is elected by citizens.
A prime minister is the chief executive of a parliamentary democracy. He wields powers to establish and dismiss parliament and appoint officials.
==In Absolute Monarchies and Dictatorships==
In an absolute monarchy, a monarch wields absolute power. He or she is the supreme leader of the nation; his or her power is not limited by a constitution. He or she makes all the laws. 
In a dictatorship, a dictator often usurps power by force and become supreme leader. He or she makes all the laws.