To find the causes of the war we should turn not to Blue Books or White Papers, giving carefully selected statements of those responsible for concealing from the public the true issues that move nations to attack each other, but should seek the unavowed aims of those nations themselves.
Once the motive is found it is not hard to say who it is that broke the peace, whatever the diplomats may put forward in lieu of the real reason.
The war was, in truth, inevitable, and was made inevitable years ago.
It was not brought about through the faults or temper of Sovereigns or their diplomats, not because there were great armies in Europe, but because certain Powers, and one Power in particular, nourished ambitions and asserted claims that involved not only ever increasing armaments but insured ever increasing animosities.

In these cases peace, if permitted, would have dissipated the ambitions and upset claims, so it was only a question of time and opportunity when those whose aims required war would find occasion to bring it about.
As Mr.Bernard Shaw put it, in a recent letter to the press: "After having done all in our power to render war inevitable it is no use now to beg people not to make a disturbance, but to come to London to be kindly but firmly spoken to by Sir Edward Grey." To find the motive powerful enough to have plunged all Europe into war in the short space of a few hours, we must seek it, not in the pages of a "white paper" covering a period of only fifteen days (July 20th to August 4th, 1914), but in the long anterior activities that led the great Powers of Europe into definite commitments to each other.

For the purposes of this investigation we can eliminate at once three of the actual combatants, as being merely "accessories after the fact," viz.:--Servia, Belgium and Japan, and confine our study of the causes of the conflict to the aims and motives of the five principal combatants.

For it is clear that in the quarrel between Servia and Austria, Hungary is only a side issue of the larger question that divides Europe into armed camps.

Were categoric proof sought of how small a part the quarrel between Vienna and Belgrade played in the larger tragedy, it can be found in the urgent insistence of the Russian Government itself in the very beginning of the diplomatic conversations that preceded the outbreak of hostilities.
As early as the 24th of July, the Russian Government sought to prevail upon Great Britain to proclaim its complete solidarity with Russia and France, and on the British Ambassador in St.Petersburg pointing out that "direct British interests in Servia were nil, and a war on behalf of that country would never be sanctioned by British public opinion," the Russian Minister of Foreign Affairs replied that "we must not forget that the _general European_ question was involved, the Servian question being but a part of the former, and that Great Britain could not afford to efface herself from the problem _now at issue_." (Despatch of Sir G.Buchanan to Sir E.Grey, 24th July, 1914).
Those problems involved far mightier questions than the relations of Servia to Austria, the neutrality of Belgium or the wish of Japan to keep the peace of the East by seizing Kiao-Chau.
The neutrality never became a war issue until long after war had been decided on and had actually broken out; while Japan came into the contest solely because Europe had obligingly provided one, and because one European power preferred, for its own ends, to strengthen an Asiatic race to seeing a kindred white people it feared grow stronger in the sun.
Coming then to the five great combatants, we can quickly reduce them to four.