Second United Front participant Kuomintang
The Second United Front (traditional Chinese: 第二次國共合作; simplified Chinese: 第二次国共合作; pinyin: dì èr cì guógòng hézuò; lit. 'Second Nationalist-Communist Cooperation') was the alliance between the ruling Kuomintang (KMT) and the Chinese Communist Party (CCP) to resist the Japanese invasion of  China during the Second Sino-Japanese War, which suspended the Chinese Civil War from 1937 to 1945.Xi'an Incident
In 1936, Chiang Kai-shek assigned "The Young Marshal" Zhang Xueliang, leader of Northeastern Army, the duty of suppressing the Red Army of the CCP. Battles with the Red Army resulted in great casualties for Zhang's forces, but Chiang Kai-shek did not provide any support to his troops.On 12 December 1936, a deeply disgruntled Zhang Xueliang kidnapped Chiang Kai-shek in Xi'an to force an end to the conflict between KMT and CCP. To secure the release of Chiang, the KMT was forced to agree to a temporary end to the Chinese Civil War and the forming of a united front between the CCP and KMT against Japan on 24 December 1936. However, by the time Chiang arrived in Xi'an on 4 December 1936, negotiations for a united front had been in the works for two years.The China Democratic League, an umbrella organization for three political parties and three political pressure groups, also agreed to take part in the united front formed by KMT and the CCP.