Under his leadership great progress was also made in education and health care. In 1937, Time magazine awarded Chang and his wife the title of Pair of the Year. After Japan’s invasion of China in 1937, he played a role in uniting the nation against the aggressor. Following the Japanese attack on Pearl Harbor in 1941, China became an allied state and Chang was even considered by US President Roosevelt to be the guarantor of a democratic China. At that time, he channelled US military aid to fight the Japanese toward maximum resources to fight the communists, in line with his motto, "first internal pacification, and then external resistance." He is considered to be one of the "Great Four" together with Stalin, Roosevelt, and Churchill, taking part in the Cairo conference in 1943. As leader of the nationalist party, the so-called Kuomintang, he led an authoritarian regime that actively fought the national liberation movement headed by the Communist Party of China. In 1949, he fled to Taiwan after losing a civil war to communists.