Looked at from this point of view, the offensive in Alsace and Lorraine, with which the campaign on the eastern frontier opened, was not the mistake which it was considered at the time by many of General Joffre’s French and English and German critics. France could not in honour invade her great neighbour to the north of Longwy, because of the neutral barriers of Luxembourg and Belgium. But to the south of that point, or at least south of the obstacle of Metz and its defences, she could and did. Along the line where the frontiers of France and Germany march there were no considerations of loyalty to treaty obligations to deter her from attacking instead of waiting to be attacked. And that was the course on which General Joffre decided. His offensive was twofold. The advance north of the barrier of the Vosges failed. But south of them, in front of the Trouée de Belfort, intersected by the Rhine-Rhone canal and the tributaries of the Doubs and the Ill, it so far succeeded that the scene of action has remained ever since in the enemy’s country. The consequent moral and strategical gains to France are enormous. The position of the Germans would have been infinitely better than it was (even without taking into account the possibility of a consequent further advance) if they had been able to dig the almost stationary line of trenches which they have occupied since the middle of September, 1914, in the soil of France instead of in the Sundgau. After the French had mobilized their armies, their great difficulty was that they could not be sure where to expect the main attack. For many years the military experts and prophets of both countries had asserted confidently that it would come by way of Belgium; on the other hand, it was a traditional belief of the great mass of the French public that it would be made through Lorraine. Both routes were possible, both had to be taken into account, but to a certain extent, from a lingering belief in Germany’s honour as well as out of deference to the popular expectation (which, on sentimental and political grounds the French Government could hardly afford to ignore), greater provision was made for resisting the possible invasion on the eastern frontier than further north. It came, as a matter of fact, by both routes at once, but of the two main assaults, which culminated at Charleroi and Nancy on the same day, the more important and dangerous was that delivered in Flanders, where the French had relatively the smaller defensive force.