How does a monarchy differ from a republic?

The primary distinction between a monarchy and a republic lies in the nature of the head of state and the source of sovereignty.12

• Monarchy: This system is traditionally based on the rule of a single person who serves as the head of state, a position typically achieved through hereditary succession. While some monarchies are absolute, many modern examples are constitutional monarchies, where the monarch performs symbolic or ceremonial duties while political authority is exercised by elected officials.413
• Republic: In a republic, sovereignty is vested in the people, who exercise power through representatives. The head of state is not a hereditary monarch but is instead typically a president or similar official appointed through election or other non-hereditary means.21

Historically, the dichotomy between these two forms was central to political theory, with monarchies defined by the rule of one and republics by the rule of a collectivity. However, these categories have evolved; today, the term "republic" is sometimes used by states with diverse political structures, including dictatorships, while many constitutional monarchies function as stable, representative democracies.432