Expulsion from the United Nations

Expulsion from the United Nations is a procedure under Article 6, Chapter II of the United Nations Charter when a member state of the United Nations can be expelled from the organization. This can be done when a member state has persistently violated the principles of the United Nations Charter. To date, only one member state has been expelled, the Republic of China (Taiwan) under General Assembly Resolution 2758, and replaced by the People's Republic of China (PRC) in 1971.

Separately, the charter also allows suspension of a state from the membership in the United Nations General Assembly.

History
During the existence of the United Nations' predecessor, the League of Nations, the Soviet Union was expelled from the organization as the initiator of the Winter War with Finland.

Republic of China
After the Chinese Civil War and the retreat of the government of Republic of China to Taiwan, the PRC lobbied for the exclusion of the Republic of China from the United Nations. Particularly, in 1971 the PRC through its proxies passed along a letter from its Ministry of Foreign Affairs stating that Taiwan was a part of its territory that was returned after World War II, and that Beijing would "have absolutely nothing to do with the [UN]" if it adopted a position of "'two Chinas', 'one China, one Taiwan,' or 'the status of Taiwan remaining to be determined'". This claim was reiterated again during debates in the United Nations General Assembly. At the time, it was viewed as a question of representation (of which government should represent China in the UN) rather than a question of admission of the PRC. Eventually, the Republic of China was stripped of its 26-year-long UN membership and replaced by the PRC in the United Nations Security Council. The expulsion occurred despite the fact that the Republic of China had been one of the founding members of the United Nations, with diplomatic recognition of other UN members. Nonetheless, the mention of the Republic of China rather than People's Republic of China among Security Council members in the United Nations Charter has been retained since.

Proposed expulsion of Russia
After the Russian invasion of Ukraine in 2022 and adoption of General Assembly Resolution ES-11/1, the presence of Russia in the United Nations Security Council has been questioned. Specifically, it was pointed out that a permanent member of the Security Council with a veto power became a rogue state without consequence. Although the Union of Soviet Socialist Republics's membership is enshrined in Article 23 of the United Nations Charter and its veto power cannot be revoked because of Article 27 of the Charter, a mechanism has been proposed to expel Russia (which inherited the USSR's position in the UN following the disintegration of the USSR in 1991) or suspend its membership. It involves expulsion through the General Assembly, which can be done under Article 18 of the Charter because if a country loses its seat in the Assembly, it also loses its seat in the Security Council. For that, a resolution proposing Russia's expulsion or suspension should go to the General Assembly from the Security Council, under Charter's Article 12. The General Assembly then must vote by a two-thirds +1 supermajority in favor of expulsion or suspension. Under Article 27 of the Charter, when the Security Council is deliberating an issue concerning one of its members, a party to the dispute shall abstain from voting. This would prevent Russia from exercising its veto power in the Security Council prior to a General Assembly vote.