In the 1920s and 1930s China was racked by civil strife. Although the Nationalist government was established in Nanking in 1928, it exerted its power only in a small part of China, mainly in the lower Yangtze valley. When the Nanking government endeavored to unify China by force, the local warlords, who strove to maintain their own armies and bases, directed against this central government. Political divisions and tensions persisted between Nanking and the local governments until 1936.