Professor Kelsen is one of the chief exponents of this theory regarding the subjection of International Law.
Westlake remarked; “The duties and rights of the states are the only duties and rights of men who compose them”.
Kelsen is a little bit rigid in considering all the international legal rules for directly the individuals and not the state which in real has no existence without individuals. But in one way he is lenient that, state law applies on individuals intermediately whereas the international law applies upon individuals mediately.
The individuals which are particularly considered under this theory include; slaves, pirates, war-prisoners, diplomats and spies.
Phillip C. Jessup is of the point that; “While I agree that states are not the only subjects of international law, I do not go to the other extreme and say that the individuals are the only subjects”.
International Court of Justice lays emphasis on one of the elementary principles of International Law that; “A state is entitled to protect its subjects when injured by acts, contrary to international law committed by another state from whom they have been unable to attain satisfaction through the ordinary channels”.
In this holding, the court has pointed out that state is fundamental subject of international law rather than individual which is ought to get justice through state.