Everything pointed to the time as ripe for the fulfilment for the Allies of the tactical dream which had called Ludendorff to his own ambitious campaign in the spring of 1918. Marshal Foch would now broaden his front of alternating attacks from Verdun to the North Sea, in the hope of freeing the Allied armies from trench shackles for a decisive campaign in the open. The American part in this bold undertaking was to be its boldest feature.
If a soldier from Mars had come to Earth at any time from October, 1914, to October, 1918, and had been shown on a flat map the fronts of the two adversaries, he would have said that the obvious strategic point of a single offensive would be between the Meuse River and the Argonne Forest. This would be a blow against the enemy's lines of communication: a blow equivalent to turning his flank. If the soldier from Mars had been shown a relief map, he would have changed his mind, and he would have perfectly understood, as a soldier, why all the offensives had been in the north, from Champagne to Flanders, where breaking through the main line of defenses would bring the aggressor to better ground for his decisive movement in the open. He would also have understood why the front from the Argonne to the Swiss border had been tranquil since the abortive effort of the Germans at Verdun.
When Ludendorff undertook his great offensive of March, 1918, he did not repeat Falkenhayn's error, but turned to the north, where the Allies had made their attacks. In that Lorraine-Alsatian stalemate to the south, with the Vosges mountains and interlocking hills from Switzerland to the forts of Metz as the stronghold of the Germans, and the forts of Verdun, Toul, Epinal, and Belfort as the strongholds of the French, the odds were apparently too much against an offensive by either side to warrant serious consideration. Yet a watch was kept. Over the French mind was always the shadow of a possible German offensive toward Belfort; and, when the sector which our young army was to hold in Alsace and Lorraine had been first discussed in July, 1917, the French excluded the defense of a portion of the front opposite Belfort, with the polite explanation that they preferred to hold that themselves. But the Germans never did more than make the feint of an offensive in the south, which Ludendorff used in the winter of 1918 to draw off French troops and guns from the north: for the army with the numbers and the initiative of offense can always force the defense to waste movements to meet threats of attack. This was another advantage which the Allies could now use in keeping Ludendorff in doubt as to where our real blows were to be struck.
The heights of the Saint-Mihiel salient, which look directly across the plain of the Woëvre to the fortress of Metz, may be said roughly to have formed the left flank of the Lorraine-Alsatian stalemate. They continue onward in the hills which are crowned by the forts of Verdun, and then across the Meuse River for a distance of twenty miles through the bastion of the Argonne Forest, where they gradually break into the more rolling country of Champagne. The Meuse winds past Saint-Mihiel and through the town of Verdun, and then, in its devious course, swings gradually to the northwest until, at Sedan, it turns full westward.
Our new offensive was to be between the Meuse River and the western edge of the Argonne Forest. East of the forest is the little river Aire, and between its valley and the valley of the Meuse rises back of the German front a whale-back of heights, as I shall describe them for the sake of bringing a picture to mind, though the comparison is not absolute. The practical summit of the whale-back is to the eastward of the village of Buzancy. We may use Buzancy as a symbol: for it is only in a highly technical history that the detail of names, confusing to the general and even the professional reader, is warrantable. The summit of the whale-back gained, you are looking down an apron of rolling ground and small hills toward the turn of the Meuse westward past Sedan, where the German Army surrounded the French Army in the Franco-Prussian War.
To the northeast, readily accessible to attack, are the Briey iron-fields, which were invaluable to the Germans for war material. Along the valley of the Meuse after it turns westward, and along the Franco-Belgian frontier runs the great railroad from Metz to Lille, which is double-track all the way and in large part four-track. Incidentally this connected the coal fields of northern France with Germany, but its main service was to form the western trunk line of communication for the German armies in Belgium and northern and eastern France. It was linked up with the railways spreading northward into Belgium and southward toward Amiens and Paris in the arterial system which gave its life blood to the German occupation. If this road were cut, the German troops in retreat would have to pass through the narrow neck of the bottle at Liége.
The dramatic possibilities of gaining the heights of Buzancy and bringing the Lille-Metz tracks under artillery fire had the appeal of a strategic effect of Napoleonic days. The German staff had been fully aware of the danger when, in their retreat after their repulse on the Marne, which the world saw only as the spectacle of the French Army inflicting a defeat on an advancing foe, it used its tactical opportunity for choosing, with comparative deliberation, advantageous defensive positions from the Argonne Forest to the Meuse at the foot of the whale-back.
For future operations it was depending upon more than the elaborate fortifications of that line. Every hundred yards from the foot of the whale-back to the summit was in its favor in resisting attack. Higher ground leads to still higher ground, not in a regular system of ridges but in a terrain where nature cunningly serves the soldier. Nowhere might the defense invite the attack into salients with a better confidence, or feel more certain of the success of his counter-attacks. All roads, and all valleys where roads might be built, were under observation. Heights looked across to heights on either side of the two river troughs, heights of every shape from sharp ridges and rounded hills to peaked summits crowned by woods. Tongues of woods ran across valleys. Patches of woods covered ravines and gullies where machine-gunners would have ideal cover and command of ground. Reverse slopes formed walls for the protection of the artillery. The attack must fight blindly; the defense could fight with eyes open.
Had the Allies attempted an offensive in the Meuse-Argonne sector in the first four years of the war, the long and extensive preparations then regarded as requisite for an ambitious effort against first-line fortifications would have warned the Germans in time to make full use of their positions in counter-preparations. All the advantage of railroads and highways were with them in concentrating men and material. It might not be a long distance in miles from the Argonne line to the Lille-Metz railway or to the Briey iron-fields, but it was a long distance if you were to travel it with an army and its impedimenta against the German Army in its prime. When attrition was in his favor in the early period, the German might well have preferred that the Allied offensive of Champagne, or Loos, or the Somme, or Passchendaele, should have been attempted here: thus leaving open to him, after he had inflicted a bloody repulse in this sector, the better ground in the north for a telling counter-offensive.