ON THE LAW OF WAR AND PEACE (DE JURE BELLI AC PACIS), the first systematic treatise on international law, remains a great landmark in the history of modern civilization and one of the foundations of modern international law. Grotius had a three-fold reason for writing his great book. First, he was morally and philosophically concerned with the problem of war. He was not a utopian who hoped to outlaw war, which he thought a regrettable but natural thing, but a practical attorney and an erstwhile public official who hoped to regulate and mitigate the horrors of conflict. As he says in his “Prolegomena” to ON THE LAW OF WAR AND PEACE, “Throughout the Christian world I observed a lack of restraint in relation to war, such as even barbarous races should be ashamed of; I observed that men rush to arms for slight causes, or no cause at all, and that when arms have once been taken up there is no longer any respect for law, divine or human; it is as if, in accordance with a general decree, frenzy had openly been let loose for the committing of all crimes.” Grotius says that he is fully convinced “that there is a common law among nations, which is valid alike for war and in war.” He hoped that by codifying and commenting on this “common law among nations” he would be able to create a base on which war could be understood and regulated.
His second reason for writing the book was his academic pride and self-interest. Grotius was as much a scholar as he was an active and practical man of affairs. He was one of the last great humanists; that is, one of the last great classical scholars of the Renaissance variety. To a great extent his ON THE LAW OF WAR AND PEACE is a scholarly study of classical Greek and Roman literature, science, and history aimed at understanding the classical experience of war, its causes, its conduct, and its effects. In this study he hoped to demonstrate, by the use of copious classical and biblical precedents, that there was indeed a set of natural and right laws pertaining to war and its conduct. Furthermore, he was aware that other scholars had attempted to make the same kind of study, but that all had failed. To complete such a study would, if nothing else, “contribute somewhat to the philosophy of the law.”
Finally, Grotius was ambitious. He was a political prisoner during the time he wrote the work and he undoubtedly hoped that it would impress the world and lead to his being brought back to a position of power and responsibility.
While the title of the book would indicate that Grotius was concerned equally with war and peace, the parts of the book that have to do with peace are only grafted onto the whole. The practical, as opposed to the scholarly, genesis of the work was Grotius’ experience in legal conflicts having to do with the law of prize and war on the high seas. This experience developed from certain legal problems that arose when the Dutch East India Company began to make inroads on the Portuguese trade monopoly in the Far East and Southeast Asia during the first decades of the seventeenth century.
What Grotius set out to do was to construct a system of law that was not based on the old principle of authority and decree, the principle on which was based the Roman law that dominated most of European legal study and which was the foundation of the Canon Law of the Roman Catholic Church. Grotius sought to replace the principle of authority with the principle of natural law common to all men and nations. The rationale of his system runs somewhat as follows: Like Aristotle, Grotius saw man as a social animal by nature. Just as it is natural that man should form societies, it is natural that he should have laws, since society cannot exist without laws, legal rights, and a system of justice. While law is natural to man, it is a conscious product of his reason, has been developed under the control of reason, and can be developed even further than necessity has so far demanded, by the further...
(The entire section is 1638 words.)