ABSTRACT
The naturalist school of thought dominated early theories on international law and the use of force. Hugo Grotius recognised the realities of international relations and the irony that in order to maintain peace as effectively as possible, sometimes war was a necessity. The most significant development of the nineteenth and early twentieth century was a general abandonment of the belief that international law existed as a means to restrict states ability to wage war. The sovereignty of states, as recognised by Emerich von Vattel, formed the basis for positivism and thus formed the basis of international legal theory. The exceptions, recognised by Vattel himself, of the right of intervention based on treaties and on self-help and self-preservation were regularly exploited. Expansionism broke no laws because the territories being subsumed were not sovereign states and therefore played no part in the creation on international law.
