There are two schools of thoughts. One believes that sovereignty is unlimited, absolute and supreme. That is another school of thought that rejects this view. They point out many limitations of sovereignty such as:
Constitutional Limitations of Sovereignty
The constitution is the basic law of a country. Every law made by the legislature must be in conformity with the constitution otherwise such a law will be null and void. Similarly every constitution provides for the fundamental right of the citizens. These rights are inviolable.
The Sovereign cannot do certain things, which .are naturally impossible i.e. the sovereign cannot order the sun to rise in the west or cannot change the cycle of seasons. If a sovereign would claim to do that, he will be sent to the lunatic asylum.
In theory the state can do anything. It cap make any kind of law. In can declare legal things to be illegal and vice versa. But in practice there seems to be difficulties. For example the parliament can pass a law saying that all blue eyed babies should be killed. Legally this is unchallengeable but in practice the government will find it very difficult to implement it because the government will not be in a position to face the public opinion which is based on morality. Similarly the government basis its laws on morality because it feels the people would obey and respect such laws. Somebody has very rightly said: there is much difference between law in books and late in action. In short the government and for that matter, the state has to observe moral principles.
No human being is perfect. There are limits to one's mental and physical faculties. A person may be able to do certain work for a certain period of time. It is not possible for him to continue to do the same thing for an unlimited and indefinite period. A sovereign has to take into consideration these limitations. If he over-steps these limitations, people will not cooperate with him. Sovereign can make a law ordering the people to sleep during day and to work at night. People will obey such a law but for a very short period because following such a law means overstepping physical limitations of human beings.
Limitation of International law
Every state has to have relations with other states. These are regulated by a law known as International Law. Under normal circumstances every state is expected to obey international law. Non-observance of International Law would result in chaos and confusion in international field. So every state is compelled to observe International Law. In many states international law is regarded a part of the law of the land.