between the United States and China. The American military presence in Taiwan consisted of the Military Assistance Advisory Group (MAAG) and the United States Taiwan Defense Command (USTDC). Other notable units included the 327th Air Division. Until the US formally recognized the People's Republic of China in 1979, Washington provided the ROC with financial grants based on the Foreign Assistance Act, Mutual Security Act, and Act for International Development enacted by the US Congress. A separate Sino-American Mutual Defense Treaty was signed between the two governments of US and ROC in 1954 and lasted until 1979. The US State Department's official position in 1959 was: That the provisional capital of the Republic of China has been at Taipei, Taiwan (Formosa) since December 1949; that the Government of the Republic of China exercises authority over the island; that the sovereignty of Formosa has not been transferred to China; and that Formosa is not a part of China as a country, at least not as yet, and not until and unless appropriate treaties are hereafter entered into. Formosa may be said to be a territory or an area occupied and administered by the Government of the Republic of China, but is not officially recognized as being a part of the Republic of China. 1971 expulsion from the UN In 1971, the UN expelled the ROC and transferred China's seat to the People's Republic of China (PRC). In addition to the recognition of the ROC by a majority of countries before UN Resolution 2758, the ROC lost its membership in all intergovernmental organisations related to the UN. As the UN and related organizations like the International Court of Justice are the most common venues for effective execution of international law and serve as the international community for sovereign states, a majority of the countries aligned with the West in the Cold War terminated diplomatic relations with the ROC and opened diplomatic relations with the PRC. The United Nations Charter's Articles 23 and 110, in its Chapter II, explicitly refer to the ROC, but the seat of "China" is currently occupied by the PRC. The ROC continues to maintain substantial relations, including with most of the non-governmental organisations at the United Nations, in addition with the concern from UNESCO. The Vienna Convention on Diplomatic Relations was signed and ratified by the ROC on 18 April 1961 and 19 December 1969, including Optional Protocol concerning