Step 1: Understanding the Question:
The question asks to identify the ultimate or primary source of political authority and power in the Indian political system.
Step 2: Key Concept:
The concept of popular sovereignty is central to the Indian Constitution. This principle holds that the authority of a state and its government are created and sustained by the consent of its people, who are the source of all political power.
Step 3: Detailed Explanation:
The Preamble to the Constitution of India begins with the words, "WE, THE PEOPLE OF INDIA...".
This phrase explicitly states that the Constitution derives its authority from the people of India.
Elections are held at regular intervals where the public (people) elect their representatives to the Parliament and State Legislatures.
This mechanism of universal adult franchise ensures that the ultimate power remains with the citizens.
Therefore, the public is considered the main source of political power in India.
Step 4: Final Answer
Based on the principle of popular sovereignty enshrined in the Preamble of the Constitution, the main source of political power in India is the public.