 Complete the following phrase:  His month-long premiership was the subject of dispute between his supporter, Marshal Zhang Zuolin, and his detractor, General Wu Peifu. When Wu forced his resignation on January 25, 1922, it caused the First Zhili-Fengtian War. Liang was fortunate to avoid the war himself: he left Beijing under the excuse of illness as soon as he resigned. The Northern Expedition forced him to flee once again to Hong Kong in 1928, then he shuttled between Shanghai and Hong Kong until the 