At the same time, the spread of the disease directly affected the war itself. All sides lost soldiers to the flu outbreak, but Germany and Austria-Hungary were hit especially hard, with the armies of both countries becoming severely weakened just as the Allies were beginning to take the offensive. The epidemic continued well into 1919, when it suddenly died out just as quickly as it had started.
By the end of May 1918, several thousand American troops had appeared on the front ready to fight, arriving just in time to meet the latest German offensive. The U.S. forces were involved in several battles, most notably at Cantigny, on the Somme. Here, 4,000 American soldiers attacked German forces on May 28, while the French provided cover with tanks, airplanes, and artillery. They successfully liberated the town of Cantigny and then held the line during three successive days of German counterattacks. U.S. forces suffered over 1,000 casualties during the engagement.
Throughout June and early July 1918, the Germans attempted a series of offensive actions, still trying to break through the Allied defense lines in France. The lines held, however, in part due to the newly provided American reinforcements.
On June 3, a German attack at Château-Thierry was stymied by intelligence that the Allies gained from German prisoners of war. Knowing of the German plans in advance, the French created a false front line, complete with trenches. The German artillery barrage ended up landing on a set of trenches that were largely empty, and when the German soldiers rushed forward, they found themselves facing mostly fresh and unfazed Allied soldiers who opened fire upon them, leaving the Germans in disarray. Nonetheless, the Germans continued the attack over the next two days, once again threatening Paris.
The Allies responded on June 6 with a counterattack of their own, using combined forces from France, Britain, Italy, and the United States. The attack was devastating, killing over 30,000 German soldiers in twenty days. Although the battle continued for many weeks, the Germans’ will to fight was shattered, and Kaiser Wilhelm II knew that the end was looming. German troops were losing ground every day, and the Allies intensified their attacks with every opportunity. The momentum stayed with them, and they steadily drove the Germans back during all of August and September.
In the Near East, meanwhile, the tide had turned in the war with the Ottoman Empire since the devastating British defeats in Gallipoli and Mesopotamia back in 1916. Since then, Britain had captured Baghdad along with all of Mesopotamia. Farther south, on the Arabian Peninsula, revolts by desert tribesmen had broken Turkey’s long-lasting grip on the region.
In December 1917, the British captured the city of Jerusalem in Palestine and slowly began advancing toward Turkey proper. Finally, on September 19, 1918, the British launched a direct attack on the Turkish front at Megiddo and won a major victory that forced the Turks into a full-scale retreat. By mid-October, Turkey was asking for peace terms.
Although this final period of major combat saw two major developments—the Russian exit and the U.S. entrance—the degree to which these events impacted the war is debatable. By the spring of 1918, both sides’ armies were exhausted from years of fighting and had little reason to hope that an end would soon come. While there were some hints of peace discussions late in the summer, the political and military leaders of all the remaining warring countries were actively planning combat operations intended to last well into 1919.
Russia’s exit from the war gave the Germans a renewed hope of achieving victory, just as the appearance of American troops in Europe gave similar hope to the French and British; however, neither of these events really turned the tide. Rather, they effectively balanced each other out, while the catastrophic influenza outbreak placed a heavy burden on both sides. Ultimately, the real trigger for the end of the war appears to have come from the mass mutinies within the Austro-Hungarian and German militaries.