The China Theater of Operations more resembled the Soviet-German war on the Eastern Front than the war in the Pacific or the war in Western Europe. On the Asian continent, as on the Eastern Front, an Allied partner, China, carried the brunt of the fighting. China had been at war with Japan since 1937 and continued the fight until the Japanese surrender in 1945. The United States advised and supported China's ground war, while basing only a few of its own units in China for operations against Japanese forces in the region and Japan itself. The primary American goal was to keep the Chinese actively in the Allied war camp, thereby tying down Japanese forces that otherwise might be deployed against the Allies fighting in the Pacific.

The United States confronted two fundamental challenges in the China theater. The first challenge was political. Despite facing a common foe in Japan, Chinese society was polarized. Some Chinese were supporters of the Nationalist Kuomintang government; some supported one of the numerous former warlords nominally loyal to the Nationalists; and some supported the Communists, who were engaged in a guerrilla war against the military and political forces of the Nationalists. Continuing tensions, which sometimes broke out into pitched battles, precluded development of a truly unified Chinese war effort against the Japanese.
The second challenge in the China theater was logistical. Fighting a two-front war of its own, simultaneously having to supply other Allies, and facing enormous distances involved in moving anything from the United States to China, the U.S. military could not sustain the logistics effort required to build a modern Chinese army. Without sufficient arms, ammunition, and equipment, let alone doctrine and leadership training, the Chinese Nationalist Army was incapable of driving out the Japanese invaders. A "Europe-first" U.S.