Despite incessant provocation for two years, since the "Lusi tania" incident, President Wilson had held to his neutral policy, and if his excess of patience angered many of his own people it at least was the means of consolidating American opinion and reconciling it as a whole to intervention in the war. Meantime he strove by speech and by the agency of Col. House—his unoffi cial ambassador—to find a basis of peace on which the belligerents could agree. This effort was doomed to failure by its misunder standing of the psychology of the warring peoples and of the fundamental objects for which they were fighting. He was still thinking in terms of traditional warfare, between governmental policies, while the conflict had long since passed into the wider sphere of the struggle of peoples dominated by the primitive instinct of self-preservation.
The declaration of the unlimited submarine campaign brought convincing proof of the futility of these peace hopes and of the reality of the German intentions, and when followed by the delib erate sinking of American ships and an attempt to instigate Mexico to action against the United States, President Wilson hesi tated no longer, and on April 6, 1917, America entered the war against Germany.
Her potential force in man-power and material was illimitable but, even more unready than Britain in 1914, it must be long in exerting more than a moral influence, and Germany confidently anticipated that the submarine campaign would take decisive effect within a few months. How near her calculation came to fulfilment the record of 1917 and 1918 bears witness.
Among the Allied peoples and their political representatives there was a growing sense of depression. On the one hand it took the form of dissatisfaction with the conduct of the war and, on the other, of discouragement over the prospects of a victorious conclusion to the war, and a tendency to discuss the possibilities of a peace by negotiation. The first-named tendency was the first to come to a head and was signalized in London, the political mainspring of the Allies, by the replacement of Asquith's Govern ment on Dec. It by one with Lloyd George as its chief. The order
of precedence in events had a significant effect. For Lloyd George had come into power as the spokesman of a widespread demand for a more vigorous and more efficient prosecution of the war.
The second tendency received an impulse from the German peace move of Dec. 12, after the fall of Bucharest, which pro posed an opening of peace discussions. This suggestion was re jected as insincere by the Allied Governments, but it afforded the opportunity of President Wilson, on whose behalf Col. House had long been sounding the belligerent Governments as to the prospects of mediation, to invite these to define their war aims as a preliminary to practical negotiation. The German reply was evasive, the Allied replies were considered by their opponents inacceptable as a basis of discussion, and the tentative peace moves subsided.
But while this wave of depression was surging on the "home front," the Allied commanders continued optimistic. In Novem ber Joffre assembled, at Chantilly, a further conference of the commanders at which it was agreed that the Germans were in great difficulties on the Western front, and that the situation of the Allies was more favourable than it had ever been.
The fighting strength of the British army had grown to about 1,200,000 men, and was still growing. The fighting strength of the French army had been increased by the incorporation of native troops to some 2,600,000, so that, including the Belgians, it was estimated that the Allies disposed of about 3,900,00o men against about 2,500,00o Germans.
Joffre declared that the French army could maintain its strength for one more great battle, but that thereafter it must progres sively decline, as France had no longer a sufficient number of men of military age to replace losses. He therefore warned Haig that during the coming year the burden must fall more and more upon the British army. It was also agreed that in view of these factors the relative superiority of the Allies on the Western front would be greater in the spring of 1917 than at any time which could be foreseen with certainty. In consequence it was decided to take the earliest opportunity of pressing the advantage gained on the Somme, and to continue the process of exhausting the enemy's re serves as preparation for an effort which should be decisive. An alternative proposal was made by Gen. Cadorna that the French and British should co-operate in a combined thrust from the Italian front against Austria with the object of knocking this "weaker partner" out of the war. But it was rejected by the French and British commanders, despite Lloyd George's espousal of it at the Allied conference held in Rome in January. Their objection was that it involved a fresh diversion of strength away from the main front, where alone, they held, success could have decisive results.