"Publicly, Mao had sailed in the face of the American threat and, in effect, thumbed his nose at Stalin's warnings as well. In 1946, when Chiang Kai-shek began preparing an all-out drive against the Communists, Stalin urged Mao to enter into a coalition with Chiang and take a secondary role. Resistance, Stalin contended, might lead to World War III. For many years Stalin had demonstrated his preference for Chiang, as Mao bitterly knew. Stalin had supported Chiang even after he turned on the Communists in the 1927 massacre at Shanghai. Only with the greatest reluctance had Stalin shifted his backing from Chiang Kai-shek in Shanghai to the Communists and left-wingers. Mao had no illusions about whom Stalin preferred. As a contemporary Soviet historian commented: "Stalin favored a two-Chinas policy." Stalin felt Chiang was weak and posed no danger to Moscow. He did not trust Mao."