By 1938, the United States increasingly was committed to supporting China and, with the cooperation of Britain and the Netherlands, threatening to restrict the supply of vital materials to the Japanese war machine, especially oil, steel and money. The Japanese army, after sharp defeats by the Russians in Mongolia, wanted to avoid war with the Soviet Union, even though it would have aided the German war against the USSR. The Emperor became fatalistic about going to war, as the military assumed more and more control. Prime Minister Fumimaro Konoe was replaced by the war cabinet of General Hideki Tojo (1884-1948), who demanded war. Tōjō had his way and the attack was made on Pearl Harbor in December 1941, as well as British and Dutch strong points. the main American battle fleet was disabled, and in the next 90 days Japan made remarkable advances including the Dutch East Indies, the Philippines, Malaya and Singapore.