Question

Which principle asserts that citizens, not politicians or government officials, hold ultimate authority?

Answer 1

There are several different ideas throughout history that have make this case, but the most popular in the western world is the idea of "popular sovereignty", especially in democracies. 

Answer 2

The principle of Popular sovereignty asserts that citizens, not politicians or government officials, hold ultimate authority

Popular Sovereignty  is commonly known as the Squatter Sovereignty is a form of rule,  in which the Nation-State performs its powers over itself and its people.

In the context of the United States, the  Popular Sovereignty served as the primary principle of the government.  It is the belief that the power of a state is established and sustained by the acquiescence of the people by their elected representatives ( rule by the people or the democratic rule).

The most important belief of this type of power is that the authority, legitimacy and legality of the government are formulated by the consent of its people and that the people of America are the source of all political power.