The Austrian misadventure was a meagre morsel with which to fill the gap between the latest German offensives and the crowning mercy for which the German public had been led to look; and as the precious summer weeks flew by uneasiness must have filled any German minds that were capable of discerning the realities of the situation. But the wish is father to most men's thoughts, and unpleasant facts which were not concealed by the censor were sedulously ignored or explained away. "Foch's reserves" became a jesting synonym on German lips for something which did not exist, and it was the daily exercise of journalistic wisdom to show that American armies which could not swim or fly would be prevented by German submarines from crossing the Atlantic. Ludendorff was not so blind, and had he been a patriotic statesman instead of a Junker general he would have sought to make terms while he might do so with advantage. But it is the nemesis of militarism that it never can make a peace which is tolerable to its enemies, and Ludendorff had no choice but to persist with an offensive which had become a desperate gamble. His efforts since the end of May had profited him little; he had used up most of the divisions intended for a final resumption of his attack on the Franco-British liaison; and after more than a month's delay he could only launch his last bolt against an eccentric and subsidiary objective. Foiled in front of Amiens and Paris, he turned to Reims; but there was nothing in the previous history of the war on the Western front to suggest that, even were his last offensive as successful as his first, it would bring him within measurable distance of the victory he needed. The Marne might be crossed and the railway to Nancy and Verdun cut, as they had been in 1914, but the further advance for which he could hope from his attack on Reims would bring him no nearer to Paris, to breaking the Entente connexion, or to damming that fatal flow of American reinforcements which was providing Foch with as many reserves a month as Germany could recruit in a year.
The fateful attack began at 4 a.m. on 15 July after four hours of artillery preparation. Its object was to encircle the Montagne de Reims, the chief bastion of the line of communications between Paris and the eastern front on the Meuse, and to extend the German hold on the Marne from Dormans as far as Châlons. There were two converging attacks, one on the twenty-six miles of front which Gouraud held east of Reims between Prunay and Massiges, and the other on a twenty-two mile line south-west of Reims between Vrigny and Fossoy on the Marne above Château-Thierry. For each attack Ludendorff used fifteen divisions, with others in reserve. On both fronts he found Foch prepared to counter the tactics which had been so successful in the earlier stages of the offensive. The first line was lightly held, and the Germans were shaken by a skilfully arranged bombardment as they crossed the zone between it and the real French defences. Upon these in Champagne they made no impression whatever. Prunay, Prosnes, Auberive, and Tahure were yielded at first, but recovered by counter-attacks; the French lost no guns, and their casualties were insignificant. Gouraud more than anyone else had frustrated Ludendorff's last offensive. South-west of Reims the Germans were rather more successful. They pushed across the Marne to a depth of some three miles between Mezy and Dormans, and in three days advanced up it past Châtillon towards Épernay as far as Rueil. Similar progress was made eastwards on the line between the Marne and Vrigny. But the gate-posts were firmly held at Fossoy with American assistance, and at Vrigny with that of the British and Italian divisions which under Berthelot did some of their best fighting in the war. By the evening of the 17th the Entente forces were successfully counter-attacking all along the line, and at dawn on the 18th Foch delivered the blow which converted the German advance into a retreat, and began a triumphal progress which did not stop until four months later the enemy sued for peace.