Traditionally, international law had states as its sole subjects. With the proliferation over the last century of international organizations, they have been recognized as its subjects as well. More recent developments in international human rights law, international humanitarian law[?] and international trade law[?] (e.g. NAFTA Chapter 11 actions) have lead to individuals and corporations being increasingly seen as subjects of international law as well, something which goes against the traditional legal orthodoxy. Since international law increasingly governs much more than merely relations between sovereign states, it may be better defined as law decided and enforced at the international, as opposed to national level.
International law usually deals with treaties created or recognized by the United Nations. These laws apply in all member states. These laws are written by the sixth committee of the United Nations General Assembly. International law also deals with international treaties. The International Court of Justice in The Hague in the Netherlands deals with violations of these treaties and laws. After that, the General Assembly decides what to do to that country or party. Some parties do not recognize that the General Assembly has any authority to enforce violations of international law, some treaties, such as the International Covenant on Civil and Political Rights have an optional protocol that allows individuals who have had their rights violated by member states to petition the international Human Rights Committee.
In the Middle Ages it had been considered the obligation of the Church to mediate in international disputes. In the 16th and 17th centuries the Church gradually lost its influence in international affairs, as Catholic and Protestant powers emerged and struggled for dominance and survival.
Some people assert that international law developed to deal with the new states arising, others claim that the lack of influence of the Pope and the Catholic church gave rise to the need for new generally-accepted codes.
The Dominican professor Francisco de Vitoria[?] (in Latin Franciscus de Victoria) of theology at the University of Salamanca lectured on the rights of the natives. He did so while Spain was at the height of its power, after the violent Spanish conquest of Peru in 1536. Charles V, Holy Roman Emperor, protested against the friar[?], but in 1542 new laws put the natives under protection of the Spanish crown. Vitoria is generally recognized as the founder of modern international law.
The French monk Emeric Cruce[?] came up with the idea of having representatives of all countries meeting in one place to discuss their conflicts. He suggested this in his The New Cyneas (1623), choosing Venice, and suggested that the Pope should preside over the meeting. Of course, during the Thirty Years' War (1618 - 1648), this was not acceptable to the Protestant nations. Though his call to abolish armies was not taken seriously, Emeric Cruce does deserve his place in history through his foresight that international organizations are crucial to solve international disputes.
Hugo Grotius developed his ideas on international law with his Mare Liberum (Latin for "Free seas"), in which he challenged the claims and attempts of England, Spain, and Portugal to rule portions of the oceans and seas. In 1625, with his book De Jure Belli ac Pacis (The Law of War and Peace), he gained new international fame, as it became the first definitive text on international law.
Much of Grotius's content drew from the Bible and from classical history. In his work he did not condemn war as a political tool. Instead, he considered cases in which war is appropriate, and defined criteria for a 'just war':
Modern International Law has its roots in the 1648 Treaty of Westphalia. International Law continued to develop with the colonization of the New World, the American Revolution, the French Revolution, the Napoleonic Wars, and on into the 20th Century.
After World War I, the nations of the world decided to form an international body. U.S. President Woodrow Wilson came up with the idea of a "League of Nations". However, due to political wrangling in the U.S. Congress, the United States did not join the League of Nations, which was one of the causes of its demise.
When World War II broke out, the League of Nations was finished. Yet at the same time, the United Nations was being formed. On January 1, 1942, U.S. President Franklin D. Roosevelt issued the "Declaration by United Nations[?]" on behalf of 26 nations who had pledged to fight against the Axis powers. At the end of the war, representatives of 50 nations met in San Francisco to draw up the charter for an international body to replace the League of Nations. On October 24,1945 , the United Nations officially came into existence, setting a basis for all international law to follow.