When did China become a Republic?
Mongolia
After the establishment of the People's Republic of China, both countries confirmed their mutual recognition on October 6, 1949. However, the Republic of China used its Security Council veto in 1955, to stop the admission of the Mongolian People's Republic to the United Nations on the grounds it recognized all of Mongolia —including Outer Mongolia— as part of China. This was the only time the Republic of China ever used its veto. Hence, and because of the repeated threats to veto by the ROC, Mongolia did not join the UN until 1961 when the Soviet Union agreed to lift its veto on the admission of Mauritania (and any other newly independent African state), in return for the admission of Mongolia. Faced with pressure from nearly all the other African countries, the ROC relented under protest. Mongolia and Mauritania were both admitted to the UN on 27 October 1961. (see China and the United Nations)
President of the Republic of China
Following the Chinese victory in the Second Sino-Japanese War, the Nationalist Government under Chiang Kai-shek was restored in Nanjing and the KMT set out to enact a liberal democratic Constitution in line with the last stage of Sun Yat-sen's three stages of national development. The new Constitution of the Republic of China, promulgated on 25 December 1947, established a five-branch government with the office of president () as head of state. On 20 May 1948, Chiang Kai-shek was formally elected by the National Assembly to be the first term president.