The success of these efforts to reach an agreement as to certain rules and principles governing the objects and methods of war paved the way for further international legis lation. In 1874 a conference representing most of the European powers met at Brussels and framed a body of rules governing the conduct of war on land but unfortunately it was not ratified by the powers and therefore remained without international force. Nevertheless its rules exerted a strong moral influence upon the conduct of the wars which followed, and many of them found their way into the military manuals issued by various governments for the guidance of commanders and troops in the field. Moreover it became the basis of the Hague Convention of 1899 respecting the laws and customs of war on land.
The high water mark in the movement to define and codify the laws and customs of war was reached in the work of the two Hague Conferences of 1899 and 1907. The first con ference formulated and adopted three conven tions and three declarations, five of which deal with the conduct of war, the most im portant of them being the convention respecting the laws and customs of war on land. The latter convention was ratified by the govern ments of all the states represented at the con ference and was later adhered to by the gov ernments of 19 other states not represented at the conference. The conference of 1907 went much further and adopted 13 conven tions and one declaration, 10 of which relate directly or indirectly to the conduct of war. (See HAGUE CONVENTIONS). The most import ant of them was the convention respecting the laws and customs of war on rand, which was mainly a revision of the corresponding con vention of 1899.
In consequence of a clause which declared that the convention should be applicable only between the contracting parties, and then only if all the belligerents were parties, this con vention as well as most of the others of 1907 was not legally binding during the recent European War, because several of the bellig erents have never ratified it. Nevertheless. the Convention of 1899 respecting the laws of war on land is binding upon all because all the belligerents were parties to it. Moreover, it is well to remember that many of the provisions of the conventions of 1907 were not new rules but were nierely declaratory of-the existing cus tomary law and as such they were binding inde pendently of the status of the conventions in which they are incorporated — as much so • as any other well-established customary rule of the law of nations. In some cases belligerent governments during the recent war took ad vantage of the circumstances that the conven tions of 1907 were not technically binding, in order to avoid the obligations which the conventions created, but for the most part they proceeded on the theory that they were in fact binding and the governments of several of them announced at the outbreak of the war that they would observe their provisions pro vided their would do likewise.
The Hague Conventions, so far as they relate to the conduct of war, deal mainly with war on land; nevertheless several conventions were adopted relating to maritime war. Thus there was. a convention relative to the conver sion of merchant vessels into warships, a con vention relative to the laying of submarine mines, a convention governing naval bombard ments and a convention relative to certain restrictions upon the right of capture in naval warfare. The questions of blockade, contra band, visit and search, transfers of flag, de struction of prizes and others, however, were not dealt with by the Hague conventions. It thus happened, therefore, that a large part of the law of maritime warfare remained unwrit ten and in the form of custom. As there were wide divergencies of opinion and practice , in regard to some of • these matters it was of the highest importance that a general agreement should be reached in these points and the results embodied in an international conven tion. In consequence of the action of the Sec ond Hague Conference in providing for the creation of an international prize court which should apply the °rules of international law° in the decision of the cases brought before it, the necessity for agreement among the mari time powers as to what the rules of interna tional law were, so far as they related to naval warfare, was evident. Upon the initia tive of the British government, therefore, a conference representing the principal maritime powers was called to meet at London in Decem ber 1909 and it agreed upon a body of rules relating to the unsettled questions of mari time warfare mentioned above and embodied them in an act known as the Declaration of London. Unfortunately, however, when the great war broke out in Europe in 1914 none of the signatory powers had ratified the dec laration. The American government there upon proposed to the several belligerents that they agree to accept the declaration as a tem porary code and conduct their naval operations in accordance with its rules, notwithstanding that it had not been formally ratified by any of them. The governments of Germany and Austria-Hungary signified their willingness to do this provided their adversaries would do so. Inconsequence, however, of the action of the British and French governments in putting the declaration into effect with important modifi cations, i this on the face of the terms of the declaration that it should be ratified as a whole and not by piecemeal, the American govern ment withdrew its proposal and announced that in upholding its own rights it would rely upon the existing law of nations rather than upon the declaration.