coup. Cao bought the presidency in 1923 despite opposition by the KMT, Fengtian, Anhui remnants, some of his lieutenants and the public. In the autumn of 1924 the Zhili appeared to be on the verge of complete victory in the Second Zhili–Fengtian War until Feng Yuxiang betrayed the clique, seized Beijing and imprisoned Cao. Zhili forces were routed from the north but kept the center. Duan Qirui return as chief executive (1924–1926) Feng Yuxiang's defection resulted in the defeat of Wu Peifu and the Zhili clique and forced them to withdraw to the south. The victorious Zhang Zuolin unpredictably named Duan Qirui as the new Chief Executive of the nation on 24 November 1924. Duan's new government was grudgingly accepted by the Zhili clique because, without an army of his own, Duan was now considered a neutral choice. In addition, instead of "President" Duan was now called the "Chief Executive", implying that the position was temporary and therefore politically weak. Duan called on Sun Yat-sen and the Kuomintang in the south to restart negotiations towards reunification. Sun demanded that the "unequal treaties" with foreign powers be repudiated and that a new national assembly be assembled. Bowing to public pressure, Duan promised a new national assembly in three months; however he could not unilaterally discard the "unequal treaties", since the foreign powers had made official recognition of Duan's regime contingent upon respecting these very treaties. Sun died on 12 March 1925 and the negotiations fell apart. With his clique's military power in a shambles, Duan's government was hopelessly dependent on Feng Yuxiang and Zhang Zuolin. Knowing that those two did not get along, he secretly tried to play one side against the other. On 18 March 1926, a protest march was held against continued foreign infringement on Chinese sovereignty and a recent incident in Tianjin involving a Japanese warship. Duan dispatched military police to disperse the protesters, and in the resulting melee 47 protesters were killed and over 200 injured, including Li Dazhao, co-founder of the Communist Party. The event came to be known as the 18 March Massacre. The next month Feng Yuxiang again revolted, this time against the Fengtian clique, and deposed Duan, who was forced to flee to Zhang for protection. Zhang, tired of his double dealings, refused to restore him after re-capturing Beijing. Most of the Anhui clique had already sided with Zhang. Duan Qirui exiled himself