What Caused the Chinese Civil War?

The Chinese Civil War was driven by a basic contest over who would rule China, intensified by opposing political aims and social constituencies. A Nationalist-Communist alliance broke apart in 1927, and although the two sides later cooperated against Japan, their rivalry remained unresolved. Japan’s defeat in 1945 brought the contest back into a full-scale war that ended with Communist victory in 1949. 2519

A contest for power—and competing political bases

The Nationalists, or Kuomintang (KMT), and the Chinese Communist Party (CCP) both sought political authority in China. Their first alliance, formed in 1924, did not erase tensions between them. The split became violent in 1927, when Nationalist forces under Chiang Kai-shek turned against the Communists and drove them from Shanghai and underground. 25

The Communists also built support in rural areas through land policies that expropriated and redistributed land, appealing to poorer communities. That gave the two movements distinct political bases as their struggle continued. 6

The war against Japan paused the rivalry, but did not resolve it

Japanese aggression led the Nationalists and Communists to cooperate again in a United Front. Their shared opposition to Japan did not create agreement over how China should be governed or which side would control it. During the war, China remained divided among Nationalist-controlled areas, Communist-controlled areas, and Japanese-occupied territory. 21

Why fighting resumed after 1945

Japan’s defeat removed their common wartime enemy and set off a contest for control of the country. Negotiations between the Nationalist government and the Communist Party failed to settle their differences, while civil strife continued. 11314

The timeline depends on what is meant by “the Chinese Civil War.” Conflict between the two sides began intermittently in the 1920s, with the 1927 break marking a key turning point. Many summaries use 1945–49 for the decisive, full-scale phase after World War II. The war ended in 1949, when Mao Zedong proclaimed the People’s Republic of China. 291

The main causes, in brief

• A struggle for national power: The Nationalists and Communists competed to govern China. 1
• A violent break in 1927: The Nationalist attack on the Communists shattered their alliance and drove the CCP underground. 2
• Different political and social bases: Communist land redistribution helped attract support among poorer rural communities. 6
• An unresolved postwar rivalry: Cooperation against Japan did not settle who would control China, and failed negotiations were followed by renewed fighting. 11314