Amid these scenes of Hellenic turmoil Sarrail strove to prosecute his offensive in aid of Rumania. The die had been cast by the northern kingdom on 27 August, and on the 28th Rumanian troops poured over the Carpathian passes into Transylvania. This direction of Rumanian strategy was severely criticized because it did not suit our Balkan plans. Bulgaria was the foe we had in view, and Rumania, it was said, should have launched her armies across the Danube in an effort to cut the corridor and join hands with Sarrail. The criticism was unjust for other reasons than the fact that in the treaty signed on 16 August it was stipulated that the principal aim of Rumanian action should be in the direction of Buda-Pesth. Sarrail's objective was Monastir, an eccentric route to Sofia or the Danube, and the British troops along the Struma were not cast for the part of an advance towards Rumania. Bulgaria, moreover, was not yet Rumania's enemy, and had shown signs of remaining neutral. Nor is a strategical motive ever an adequate reason for making war; there must be a political justification, and the grounds for Rumania's intervention was the injury suffered by the Rumanian population in Hungary and Transylvania. She had no quarrel with Bulgaria on the score of national rights; indeed, it was rather she who ruled over Bulgars in the Dobrudja, and a Rumanian war could only be defended in principle as a crusade to redeem the Rumania irredenta north of the Carpathians. Even had it been her business to pull the chestnuts out of the fire for the Entente, it might be urged that she did her part in opening the door for a Russian attack on Bulgaria. In 1915 the Russian reason for non-fulfilment of the threats of punishment for Bulgarian treason to the Slav cause had been the obstacle of Rumanian territory. That was now removed; and a Russian advance through the Dobrudja would not only have saved Rumania from Mackensen's envelopment, but have given effect to Russia's menace against Bulgaria, facilitated Sarrail's operations, cut the corridor, and isolated Turkey. Of all the strategic failures in the war none was more tragic than this which was imposed upon Russia, partly by her internal weakness and partly by her divergent ambitions in Asia Minor. The Rumanian advance across the Carpathians would have been sound enough strategically as well as politically, had it been properly supported by her huge but unreliable neighbour.