 A wave of protests followed.The war also distracted the northern warlords from the Soviet-backed Nationalists based in the southern province of Guangdong, allowing unhampered preparation for the Northern Expedition (1926–1928), which united China under the leadership of Chiang Kai-shek.By the summer of 1924 the Zhili clique, led by President Cao Kun and supported by the military of Wu Peifu, controlled much of China proper and its internationally recognized Beiyang government.