Justifications
There exist vastly differing views on the moral basis of sovereignty. A fundamental polarity is between theories that assert that sovereignty is vested directly in the sovereign by divine or natural right and theories that assert it originates from the people. In the latter case there is a further division into those that assert that the people transfer their sovereignty to the sovereign (Hobbes), and those that assert that the people retain their sovereignty (Rousseau).
During the brief period of Absolute monarchies in Europe, the divine right of kings was an important competing justification for the exercise of sovereignty. The Mandate of Heaven had some similar implications in China.
A republic is a form of government in which the people, or some significant portion of them, retain sovereignty over the government and where offices of state are not granted through heritage. A common modern definition of a republic is a government having a head of state who is not a monarch.
Democracy is based on the concept of popular sovereignty. In a direct democracy the public plays an active role in shaping and deciding policy. Representative democracy permits a transfer of the exercise of sovereignty from the people to a legislative body or an executive (or to some combination of legislature, executive and Judiciary). Many representative democracies provide limited direct democracy through referendum, initiative, and recall.
Parliamentary sovereignty refers to a representative democracy where the parliament is ultimately sovereign and not the executive power nor the judiciary.
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