A state that is ruled by an elected citizen is called a republic. In a republic, the people choose their leaders through a democratic process, such as voting in elections. The elected leader, who is usually called a president, is responsible for making decisions and governing the country on behalf of the citizens. Unlike a monarchy or an empire, where power is inherited or held by a single ruler or family, a republic is based on the principle of popular sovereignty, which means that the people have the ultimate authority to govern themselves through their elected representatives.