Memes

When the Russian revolution failed to inspire successful revolution in the west, they reached a dillema. Trotsky feared the Russian peasantry would attack, and so wanted to go on the offensive first, forcing collectivization early, hoping that would inspire the western proletariat. Stalin wanted to build up socialism domestically, rather than attack the peasantry. The peasantry turned out to be capable allies, and thus Stalin was correct.

Stalin's insistence on supporting the KMT even later as a bullwark against Japan ended up being wrong, but it's also worth noting that the Chinese Trotskyists were wrong, wanting to attack both the KMT and Japan before kicking out Japan. Mao and the CPC formed a temporary alliance against Japan, then kicked out the KMT, which ended up being correct.