Decisions in Tokyo were controlled by the Army, and then rubber-stamped by Emperor Hirohito; the Navy also had a voice. However, the civilian government and diplomats were largely ignored. The Army saw the conquest of China as its primary mission, but operations in Manchuria had created a long border with the Soviet Union. Informal, large-scale military confrontations with the Soviet forces at Nomonhan in summer 1939 demonstrated that the Soviets possessed a decisive military superiority. Even though it would help Germany's war against Russia after June 1941, the Japanese army refused to go north. The Japanese realized the urgent need for oil, over 90% of which was supplied by the United States, Britain and the Netherlands. From the Army's perspective, a secure fuel supply was essential for the warplanes, tanks and trucks—as well as the Navy's warships and warplanes of course. The solution was to send the Navy south, to seize the oilfields in the Dutch East Indies and nearby British colonies. Some admirals and many civilians, including Prime Minister Konoe Fumimaro, believed that a war with the U.S. would end in defeat. The alternative was loss of honor and power.