Legal sovereignty is that authority of the state which has the legal power to issue final commands. It is the authority of the state to whose directions the law of the State attributes final legal force. In every independent and ordered state there are some laws which must be obeyed by the people and there must be a power to issue and enforce these laws. The power which has the legal authority to issue and enforce these laws is legal sovereignty.
Popular sovereignty can be defined roughly as “the power of the people” in a modern representative democracy government, or in other words, the whole mass of the people or the electorate or the public opinion.
Popular sovereignty roughly means the power of the masses as contrasted with the Power of the individual ruler of the class. In popular sovereignty, public is regarded as supreme.
Nominal arid Real Sovereignty - In ancient times many states had monarchies and their rulers were monarchs. They wielded absolute power and their senates and parliaments were quite powerless. At that time they exercised real sovereignty. Therefore, they are regarded as real sovereigns.