The members of the UN are nations, not governments. Whereas the UN may concern itself with the character of a government at the time that a nation applies for admission and may occasionally defer admission on these grounds (Spain under the Franco government, for example, applied for membership in 1945–46 but was not admitted until 1955), once a nation becomes a member, any governmental changes thereafter do not affect continuance of membership—provided, of course, that the nation continues to fulfill its Charter obligations. Nor, under the Charter, is the admission of a new nation dependent upon whether other nations individually recognize and have diplomatic relations with the government concerned. Though the relations of individual members with a nation applying for membership will affect the voting in the Security Council and the General Assembly, strictly speaking, the only consideration enjoined by the Charter is the judgment by the members that the applying nation as represented by its government is "willing and able" to carry out its UN obligations. As a result, there are several nations in the UN that do not recognize or have diplomatic relations with each other.
Nations have to be represented at UN proceedings by delegations that are specifically authorized by their governments to speak on their behalf. Thus, when a new ambassador appears, or when a new session of a UN organ convenes, it is necessary to examine the credentials of persons claiming to represent member states. The nine-member Credentials Committee, appointed by the General Assembly at the beginning of each session, must be satisfied that the person was duly appointed by his or her government and that that government is the official government of the respective member nation. The matter can become controversial at the UN if, for example, two rival governments both claim to be the only legitimate government of a member state and each demands that its own representative be seated.
A case in point was China. The long unresolved issue of its representation in the UN had been one of the most important and controversial items on the General Assembly's agenda. In 1971, however, the General Assembly decided "to restore all its rights to the People's Republic of China and to recognize the representatives of its government as the only legitimate representatives of China to the United Nations, and to expel forthwith the representatives of Chiang Kai-shek from the place which they unlawfully occupy at the United Nations and in all the organizations related to it."