Britain and France wanted the U.S. troops to be integrated into their own armies and sent to the front to fight, but the U.S. government insisted that its troops would fight only as an independent army under U.S. commanders. Because this setup would take a long time to organize in an overseas environment, the policy drew bitter criticism from the French and British, who were still fighting the brunt of the war. The official U.S. entrance into the war in 1917 had given the Allies hope in the face of Russia’s exit. But in light of the slow pace of actual U.S. entry, many in France and Britain feared that they might lose the war before the American troops ever fired a shot.
At a meeting of the Supreme War Council of Allied Leaders on May 2, 1918, there was a small shift in the U.S. stance. General John J. Pershing, the commander of American forces in Europe, agreed to a compromise, pledging to send 130,000 troops that month and several hundred thousand more in the coming months to fight on the front with the French and British forces. This commitment mean that roughly one-third of the American forces present in Europe would see action that summer. U.S. leaders estimated that the rest, however, would not be organized, trained, and ready to fight until the late spring of 1919.
Although Russia was fully out of the war, much unfinished business remained in the territories along the old eastern front. On May 7, 1918, Romania signed a peace treaty with the Central Powers, giving up control of the mouth of the Danube River along the Black Sea coast. At the same time, German troops advanced to the southeast, through the Ukraine, southern Russia, and on to the Caucasus region. The Bolsheviks still did not have an effective hold on this region, so the Germans were able to proceed largely unchallenged.
On May 12, Germany and Austria-Hungary signed an agreement to share in reaping economic benefits from the Ukraine. Barely a week later, however, Austria-Hungary experienced the first in a series of mutinies in its army, carried out by nationalist groups. The first mutiny involved a group of Slovenes; almost as soon as it was suppressed, other mutinies broke out, led in turn by Serbs, Rusyns (Ruthenians), and Czechs.
During the summer of 1918, an unusually severe strain of influenza spread rapidly around the world. Although influenza was not normally associated with high mortality rates, this strain was especially virulent, and it would eventually kill millions of people.
The cause of the outbreak is unknown, but the war was most certainly a contributing factor. First, the war encouraged large-scale movements of people back and forth around the globe, which accelerated the spread of the virus. Second, it is thought that the numerous war-ravaged regions of the world experienced poorer nutrition and less sanitary conditions, leaving their populations especially susceptible.