It was here that his main strategic objective lay. The thrust against the Niemen had been simply designed to drive the Russians out of Prussia and protect the left of the German offensive to the south on the Narew and Warsaw. Since the German failure in December a Russian army had been pushing slowly down the right bank of the Vistula in front of Plock. This movement was checked in February, and the Germans hoped by an advance from Mlawa to get across the Narew south of Pultusk. The centre of the Russian defence was at Prasnysz where eight roads meet, but the defending force was weak, and on 24 February the Germans captured the town. But the extreme Russian left made a heroic stand on the ridge between Prasnysz and Ciechanow against Germans in front and on both sides of them. Their resistance produced a situation somewhat resembling that at Lodz, for a rapid concentration of Russian reinforcements swept round to the help of the flank at Ciechanow, while others attacked the German left at Krasnosielce. The Germans encircling Ciechanow found themselves encircled at Prasnysz, and as at Lodz they had to fight desperately for three days to escape. They were assisted by the rudimentary equipment of the Russian forces; rifles and ammunition were scarce, bayonets and hand-grenades were none too plentiful, and some of the privates are even said to have fought with pitchforks. By such hand-to-hand and bloody warfare the Germans were driven out of Prasnysz back towards Stegna and Chorzele and their flank attack on Warsaw foiled. Ruszky's strategy and Russian heroism had gained one of the most singular victories in the war.

At the other end of the Russian front, along the Carpathians, politics were beginning to exert a powerful influence upon strategy. South-Eastern Europe was reacting to the Serbian successes in December, and Rumania, like Italy, and with similar Latin feelings, was negotiating with the Entente about terms of intervention. On 27 January a loan of five million pounds was arranged by Great Britain, and while we provided financial inducements Russia dispatched a sympathetic force to overrun the Bukovina, a country kindred to Rumania which she might acquire by co-operation. There would be little risk in joining the war if Russian armies could debouch from the Carpathians; and the intervention of Rumania would link up the Serbians with the Russians and envelop unfortunate Hungary on three sides. But the spring was not yet, and Rumania would wait and see. Her king was a Hohenzollern, and his people were divided in their sympathies. If there were Rumanes under Magyar rule across the Transylvanian Alps, there were also Rumanes under Russian rule across the river Pruth; and the filching of Bessarabia by Russia in 1878 still rankled in the Rumanian mind. Bratianu, the Prime Minister, was a cautious statesman, quite capable of seeing that the occupation of the Bukovina by the Russians was a political demonstration rather than a proof of military capacity to burst the Carpathian barrier. But another argument was thus adduced to show the Prussians the need of victory in the East unless they wished the defence of their two existing fronts to be complicated by another in the south. Hungary was their chief economic, political, and military bastion outside their own dominions, and the subtle bond between Magyar and Prussian notions of government, which gave them a common interest in the war, was now drawn closer by the appointment of Tisza's henchman, Count Burian, as Foreign Secretary to the Hapsburg Empire. For Tisza, the Hungarian Premier, was in all but nationality a Prussian Junker, and his domination depended as much upon a Teutonic victory over the Slavs as a Teutonic victory did upon the retention of the Hungarian granary and a bulwark in the south.

The Carpathians were therefore the key to the future of the war and history of south-eastern Europe. The Russians had in the autumn established a solid control of the Galician outlets from the mountain passes, but had made no serious attempt to achieve the far more difficult task of securing command of the foothills south of the range, which alone would enable them to conquer the plains of Hungary. For a mountain pass is like a river bridge-head; one may often possess it without being able to debouch. The Austrians experienced that difficulty in their winter offensive against the Russian flank in Galicia. They made little progress against Brussilov at the Dukla and Lupkow passes, but farther east they seized most of the mountain routes, and Alexeiev was pressed back in Bukovina. Their centre under Linsingen was, however, held up by the Russians at Hill 992 near Kosziowa, and all efforts to dislodge the defenders failed. This defence saved Galicia for the time and prevented the relief of Przemysl, which otherwise would have been certain. For the Austrian right succeeded late in February in recovering Czernowitz, Kolomea, and on 3 March, Stanislau. Reinforcements, however, now reached the Russians; Stanislau was recaptured, the Austrians lost much of what they had gained, and on the 22nd Przemysl weakly surrendered. Its fame as a fortress had been enhanced by its five months' siege since October, but it did not redound to the credit of its defenders. They were superior in numbers to the besiegers, were amply provisioned, and well supplied with heavy artillery and all the munitions of war. Every sort of blunder seems to have been committed by the commander, who apparently regarded the siege as a relief from more arduous work in the field, and capitulated because the repulse of the rescuing expedition foreboded an increase of inconvenience.

The surrender liberated the besieging force for operations elsewhere, and the Russians began a serious effort to surmount the Carpathian rampart. They got well to the south of the Dukla, made substantial progress in the centre through the Rostoki pass, and by the middle of April held the crests for a continuous seventy miles; cavalry penetrated much farther down the slopes, and the Austrians prepared to evacuate the Ungvar valley. Reciprocal raids occurred elsewhere on the Eastern front: the Russians seized and burnt Memel, and the Germans retaliated by the bombardment of Libau. Despite warnings like that of "The Times" Petrograd correspondent on 13 April to the effect that the Germans had not only sent enormous reinforcements to the Carpathians, but had taken charge of the operations, there was general confidence in the West in a coming triumphant Russian offensive. Dmitrieff himself had no suspicion of what was in store until a few days before the storm broke; and a Panslav society in Petrograd passed and published abroad a resolution that in view of the victorious progress of the Russian armies across the Carpathians, the contemplated intervention of Italy in the war was belated and undesirable.

The Russian Government cannot have been ignorant of the weakness of Russian armies, not in man-power, still less in skill or courage, but in artillery and equipment; but it had no conception of the material and mechanical force which Germany was prepared to bring to the urgent task of relieving the pressure on her ally. Nor was it for nothing that Turkey had been cajoled and bribed into making war. Turkish generalship and organization were negligible quantities, but Germany could supply those defects, and Turkish bravery and man-power could be used as a valuable means of distracting Russia's attention and diverting forces from the Polish and Galician fronts. This had been the main purpose of the campaign in the Caucasus which Turkey waged in the winter. They began by seizing Tabriz in the province of Azerbaijan, which though nominally Persian had been for some time occupied partly by Russian and partly by Turkish troops; but the Russians were first across the Russo-Turkish frontier and captured Bayazid, Khorasan, and Kuprikeui. These advance-guards were, however, pushed back by the Turks, whose leader and evil genius, the half-Polish and German-educated adventurer, Enver, had conceived an ambitious design of encircling the Russian armies between Sarikamysh and Ardahan. In December the Turks succeeded in making their arduous way across the snow-clad mountains, and on 1 January they were in Ardahan. But the task would have tried the German Army itself in summer, and Enver had attempted more than he could achieve. His army corps were successively isolated and defeated in a series of engagements collectively known as the battle of Sarikamysh, and driven back across the frontier with heavy losses. Tabriz was reoccupied by the Russians, though they were not able to follow up their victory by the capture of Erzerum (see Map, p. 182).

The other diversion, which the Turks were used to create against the Entente, was in Egypt. British rule, in spite of the vast benefits it conferred, was not universally acceptable to the Egyptian people and still less to Egyptian officials; and chief among those who resented their restriction to the straight and narrow path of honest administration was the Khedive Abbas II. He threw in his lot with the Turks, and was deposed in his absence, while the shadowy Turkish suzerainty over Egypt was converted into a substantial British protectorate. Cyprus, which had been in British occupation since 1878, was annexed at the same time to the British Crown. The Turks had been deluded by the Germans with hopes of recovering their ancient control of Egypt, and they at once began their feeble efforts to realize their ambitions. In November an expedition started from Palestine to cut the Suez Canal, a main artery of the British Empire, and stir the embers of Moslem fanaticism in Egypt. It disappeared in the sands of the intervening desert. Another, better prepared with German assistance, reached the east bank of the Canal at various points on 2 February, but miserably failed to effect a crossing; its only success was its escape, which was partly explained by a sandstorm, and Egypt had rest until the winter brought the campaigning season round again (see Map, p. 352).

The British retort to Egypt and the Caucasus lay in the Persian Gulf and the Dardanelles. The Persian Gulf had long been a scene of British trade and political enterprise to which the inertia of its rulers rendered Persia susceptible; and its position as a possible Russian outlet to the sea on the flank of our communications with India had produced some rivalry for Persian favours. The advent of a third comer in the shape of the Germans, with their plans for a Germanized Turkish Empire controlling the Berlin-Baghdad route, changed the rivalry into co-operation; and an attack on the Turks at the head of the Persian Gulf was an obvious reply to the Turkish campaign in the Caucasus. It afforded an easy means of employing the native Indian army in the common cause without the long sea journey to France or the risks inflicted by northern winters upon sub-tropical races. During the first half of November detachments of the Indian army sailed up the Shat-el-Arab, the joint estuary of the Tigris and the Euphrates, defeated the Turks at Sahil on the 17th, occupied Basra on the 22nd, and cut off Kurna, which surrendered on 9 December. The local Turks were weak in numbers and equipment, and distance removed them from the stimulus of Enver's energy and German organization. It was not until April 1915 that an effective reaction to the British advance was attempted. Then the Turks and Arabs concerted a movement against the whole line stretching round from Ahwaz within the Persian frontier to Shaiba south-west of Basra. The real attack was on Shaiba, and the battle lasted from 12 to 15 April. The Turks were completely defeated, with some 6000 casualties; but the most important effect was to convert the Arabs into our allies. The advantage was pressed in June, and on the 3rd Amara was captured seventy-five miles to the north of Kurna. The way was open for an advance on Baghdad as soon as autumn made exertion possible in that torrid zone (see Map, p. 177).

Sir John Nixon's success in the Mesopotamian delta was, however, but a pin-prick in a distant part compared with the blow that was aimed at the heart of the Turkish Empire in the Dardanelles; and the merits of that famous but ill-starred enterprise, and of the strategy which inspired it, have been one of the most debated questions of the war. Soldiers and civilians, writers and talkers, and even thinkers were divided into two camps, Westerners and Easterners, those who believed that the war could only be won by frontal attack in the West, and those who discerned a way round to victory in the Near or the Farther East. Volumes might be, and no doubt will be, written on this controversy, and its implications have infinite variety. It involved questions of policy as well as strategy, and therefore raised the delicate problem of the relations between civil and military authority. The soldier only deals with armies, and in the field his voice is properly supreme; but policy may be as far above strategy as strategy is above tactics; and policy may dictate a strategy which would not commend itself on military principles. The soldier has nothing to do with the policy, but policy and diplomacy may or may not bring fresh allies into the war and fresh armies into the field; and a strategy which may be unsound on purely military grounds may be completely justified by political reasons. The diversion of a force from the main field of operations where it is needed to a more distant objective, seems suicidal to the general in command; but if, without provoking disaster on the field it has left, it has the effect of turning the enemy's flank, detaching his actual or deterring his potential allies, and inducing neutrals to intervene, it may win a war although it postpones or risks the success of a campaign.

On the other hand, it was urged that the fundamental principle of strategy is to concentrate all available forces where the enemy has concentrated his, beat him there, and thus win a victory which will carry with it the desired results in all the subsidiary spheres. Germany once beaten in the West, it was argued, there would be no need to trouble about the Balkans or the amateur strategy which looked to Laibach or Aleppo as the vital spot in the situation. This principle was erected into a dogma, and dogma is a dangerous impediment to the art of war. War is an art, and therefore consists in the adaptation of varying means to conditions which are not constant. Strategy is not, apart from its mechanical adjuncts, a science in which properties are fixed, axioms can be assumed, and the results of experiments foretold; the combination of two armies and a commander-in-chief does not produce the same uniform result as the combination of two parts of hydrogen and one of oxygen; and formulae are as irrational in war as in any other human art. Dogmas deduced from the experience of some wars are inapplicable to others; and the science of wars between France and Germany becomes mere imposture when it seeks to dictate dogma to wars in which the British Empire is involved. The particular dogma about concentration had three defects: it left the initiative to the enemy, thus surrendering the advantage, secured by the command of the sea, of being able to strike in other directions; it assumed that the enemy could be beaten on that front without disturbance on his flanks or in his rear; and it abandoned the Near and the Farther East to any schemes on which the Germans might choose to employ their own or their allies' subsidiary forces.

No one, on the other hand, imagined that the Western front could be denuded of the armies required to maintain it. The question was really how to use the considerable margin of force between what was essential for defence and what was needed for a successful offensive. Should it be employed for frontal attack in the West, or flank attack in the East? Caution counselled one course, adventure suggested the other. Surplus force intended for an offensive on the West would be available, if need arose, for defence; it would not, if it were a thousand miles away, and our needs in the spring of 1918 seemed to supply an effective answer to arguments drawn from our later successes in the Balkans and in Syria. The antithesis is, however, largely a false one, due to the exigencies of popular debate and the habit of treating war as an abstract science independent of changing but actual conditions. No one denies that a diversion of our main effort from France to Laibach in the winter of 1917 would have been fatal to us in the spring of 1918, but it is not clear that the thousands of troops we lost at Loos and the French in Champagne in the autumn of 1915 might not better have been employed in saving Serbia or forcing the Dardanelles.