five permanent members of the Security Council were the Republic of China, the Provisional Government of the French Republic, the Soviet Union, the United Kingdom and the United States. There have been two major seat changes since then. China's seat was originally held by Chiang Kai-shek's Nationalist Government, the Republic of China. However, the Nationalists were forced to retreat to the island of Taiwan in 1949, during the Chinese Civil War. The Chinese Communist Party assumed control of mainland China, thenceforth known as the People's Republic of China. In 1971, General Assembly Resolution 2758 recognized the People's Republic as the rightful representative of China in the UN and gave it the seat on the Security Council that had been held by the Republic of China, which was expelled from the UN altogether with no opportunity for membership as a separate nation. After the dissolution of the Soviet Union in 1991, the Russian Federation was recognized as the legal successor state of the Soviet Union and maintained the latter's position on the Security Council. Additionally, France eventually reformed its government into the French Fifth Republic in 1958, under the leadership of Charles de Gaulle. France maintained its seat as there was no change in its international status or recognition, although many of its overseas possessions eventually became independent. The five permanent members of the Security Council were the victorious powers in World War II and have maintained the world's most powerful military forces ever since. They annually topped the list of countries with the highest military expenditures. In 2013, they spent over US$1 trillion combined on defence, accounting for over 55% of global military expenditures (the US alone accounting for over 35%). They are also among the world's largest arms exporters and are the only nations officially recognized as "nuclear-weapon states" under the Nuclear Non-Proliferation Treaty (NPT), though there are other states known or believed to be in possession of nuclear weapons. The block of Western democratic and generally aligned permanent members (France, the UK and the US) is styled as the "P3". Veto power Under Article 27 of the UN Charter, Security Council decisions on all substantive matters require the affirmative votes of three-fifths (i.e. nine) of the members. A negative vote or a "veto" by a permanent member prevents adoption of a proposal, even if it has received the required votes. Abstention is not regarded as a veto in