At the beginning of September, Pétain, agreeing with most Allied political and military leaders, thought that Germany had the capacity to continue the war into 1919 even if the Allies breached the Hindenburg Line. French intelligence identified a series of new German defensive positions still to be overrun. And the arrival of winter might give the exhausted German Army a respite to rest and reinforce its spent divisions. On September 8, the French commander-in-chief wrote the following: “When the battle commences again in 1919 our adversary undoubtedly will be established behind a strongly fortified front, abundantly supplied with means of defending against tanks and covered by a deep zone of advance posts or by lines of water.” American manpower made Pétain confident of ultimate victory but he placed even greater emphasis on the growing material disparity between the opposing armies. “The battle of 1919,” he predicted, “will be a battle of aviation and tanks.”

With Allied forces maintaining the offensive initiative, however, September turned out to be a calamitous month for Germany’s military fortunes. Berlin had begun the month with more than 2.5 million men in uniform and all of its allies still in the war. Gray-clad infantry occupied more French and Russian territory than they had during the previous September and possessed the strongest defensive system on the Western Front, which remained intact. But setback followed setback, and Ludendorff’s darkening mood mirrored the bleak prospects facing German soldiers by the end of the month.