The Entente plan for 1917 was soon to be complicated by changes in the command. French opinion had tired of the meagre results of Joffre's attrition strategy, and the method of the limited objective had fallen into disfavour because of the un limited losses on the wrong side, which accompanied it without apparent gain. They contrasted the dull course of his strategy with the brilliant results gained by Mangin at Verdun, in the autumn, under Nivelle's direction, and as a result Joffre gave place to Nivelle, who promised a real break-through. His con fidence so inspired Lloyd George, the new British prime minister, that Haig was subordinated to him for the forthcoming opera tions—an arrangement which violated the axiom that a general cannot direct one force while exercising executive command of another. For carrying out a plan essentially audacious, Nivelle had two further handicaps ; he failed to convert several of his subordinates to the idea, and he was given less rein by the Gov ernment than his predecessor. Again, while Joffre had intimated that the British must take the chief part, Nivelle changed this policy, and in his desire to conserve the glory for France over looked how severely the French fighting power had been strained. Joffre's plan had been for a convergent attack on the great Ger man salient Lens-Noyon-Reims, first against its west flank and then against its south—the British to attack north of the Somme, including but extending beyond the old battle ground, and the French south of it to the Oise. The attacks were to begin early in February and to be followed by a French main attack in Champagne. Nivelle's change was to ask the British to take over more of the front—south of the Somme—in order to release French troops for the Champagne blow, and as a result the start was postponed a month.
Before it could begin the Germans had dislocated it. Luden dorff's first step had been to set on foot a complete programme for the reorganization and expansion of German man-power, munitions and supplies. While this was developing, he intended to stand on the defensive, hoping that the new submarine campaign would either decide the issue or pave the way for a decisive blow on land when his new reserves of men and material were ready. Anticipating the renewal of the Entente advance on the Somme, he had a new line of defence, of great artificial strength, built across the chord of the arc Lens-Noyon-Reims. Then after devastating the whole area inside the arc, he began a methodical retirement, by stages, to the new line called by the Germans the "Siegfried", and by the Allies the "Hindenburg" line. A con summate manoeuvre, if brutal in application, it showed that Ludendorff had the moral courage to give up territory if cir cumstances advised it. The British, confronted with a desert, were inevitably slow in pursuit, and their preparations for an attack on this front were thrown out of gear, limiting them to the sector around Arras (q.v.), where the front was unchanged.
On April 9 Allenby's 3rd Army opened the spring offensive at this point, taking the long-sought Vimy ridge, but failed to de velop its initial success, and continued the attack too long after the resistance had hardened. This costly action was partly pro
longed in order to take the pressure off the French. For the French blow between the Somme and the Oise had been stulti fied by the German retirement, and the main attack on April 16 east and west of Reims (see CHAMPAGNE, BATTLES IN) was a worse fiasco with a dangerous sequel. With a prolonged bom bardment giving away any chance of surprise, and without first drawing away the German reserves, the idea of a rapid break through was doomed to fail. The high hopes that had been raised caused the greater reaction, and the troops were weary of being thrown against barbed wire and machine-guns to no apparent effect. Accentuated by service grievances, mutinies broke out in the French armies, and no less than 16 corps were affected. In these circumstances Nivelle was replaced by Petain, whose first concern was to restore the shaken morale of the French troops, and for the rest of the year the British bore the brunt of the campaign. Their strength in France was now at its highest-64 divisions, supplied with an abundance of artillery and ammuni tion. The strain, however, was increased by the failure of Russia to make any effective contribution to the pressure on Germany, owing to the revolution which broke out in March. Haig decided to keep the Germans occupied by carrying out the original plan for an offensive in Belgium, and if the principle was right the method and choice of site were open to criticism.
The initial move was an attack on the Messines (q.v.) ridge in order to straighten out the Ypres salient and attract the enemy's reserves. Carried out by the znd Army under Plumer, with Har ington as chief of staff, it proved a model example of the "limited" attack with success economically gained by able staff work and co-operation between the arms. It was followed on July 31 by the main attack at Ypres (see YPRES, BATTLES OF, 1917) which, hampered by the heavy rain, was foredoomed by its own destruction of the intricate drainage system of the area. The British command had persevered for two and a half years with the method of a prolonged preparatory bombardment, believing that quantity of shells was the key to success, and that, unlike all the great captains of history, they could disregard the element of surprise. The offensive at Ypres, which was finally submerged in the swamps of Passchendaele in early November, threw into stronger relief than ever before the fact that such a bombardment blocked the advance for which it was intended to pave the way—because it made the ground im passable. The discomfiture was increased by the new German method of defence, which Ludendorff introduced, of thinning the front defences and using the men so saved for prompt local counter-attacks. The defence was built up of a framework of machine-guns distributed in concrete "pill-boxes" and disposed in great depth. On the British side the profitless toll of this struggle in the mud was to some extent mitigated by better staff work when the direction of the attack was handed over to Plumer's znd Army.