wrote an open letter defending Borodin, the communists, and the KMT's relationship with the Soviet Union. The following year, however, Borodin gradually came into conflict with Chiang, who was vying for the position of Sun's successor. Borodin initially opposed Chiang's planned Northern Expedition to reunify China, and grew concerned about Chiang's growing standing in the NRA. When Borodin went north in another attempt to bring Feng Yuxiang and his Guominjun into the Kuomintang in early 1926, Chiang began preparations to consolidate his position in Guangzhou. Borodin's fears were then realised in March 1926, when Chiang launched the "Canton Coup" purge of hardline leftists who opposed the launch of the expedition. Following the purge, Borodin returned from the north on Chiang's request, began negotiations, and reached a narrow compromise to hold the First United Front together. On Joseph Stalin's suggestion, Borodin agreed to continue Soviet aid to the KMT, and to support the Northern Expedition, which began in July 1926. At a Comintern conference in November 1926, Stalin explained his continued support for the KMT, saying that "The exit of Chinese communists from the Kuomintang would be the gravest error", going on to argue that the CCP needed to work through the new government, forming a bridge between the state and the peasantry. Borodin agreed, noting that the purpose of the Northern Expedition was "not the establishment of a proletarian state, but the creation of conditions which would give an impetus to the mass movement". In Borodin's view, the goal of the China mission was to facilitate a bourgeois-democratic revolution led by an alliance of workers, peasants, petite bourgeoisie and bourgeoisie, so as to create the conditions necessary for a future proletarian revolution. With tensions between the left and right threatening to break into armed conflict in Guangzhou, Borodin became convinced that it was necessary to expand the base of the anti-imperialist movement, providing adequate space for both factions. For this reason, he had agreed to support the Northern Expedition. Borodin and a group of Soviet military advisers led by Vasily Blyukher (known by the alias "Galen") were responsible for planning the expedition. Whilst Chiang Kai-shek had been named commander-in-chief of the National Revolutionary Army, he was not personally involved in the planning phase of the operation. Having studied the history of the mid-19th century Taiping Rebellion, Borodin decided that the expedition should head inland toward Hankou, an industrial and commercial