SOVIET disintegration has grave implications for the United Nations Security Council, which so recently played a vital role in resolving the Persian Gulf crisis. The breakup of a permanent council member, or its internal transformation, raises serious questions under international law. A failure to resolve these issues quickly could undermine global stability.A complete breakup of the Soviet Union, eliminating the central government, would presumably leave a number of independent states. But the UN Charter assigns permanent membership on the Security Council to the USSR, meaning the federal union. With permanent membership on the council comes the right to veto substantive decisions, such as whether to engage in an enforcement action. The UN Charter assigned permanent council membership to reflect the world balance of power. A veto for each of the five permanent members was designed to make sure that council decisions could be carried out effectively, without a conflict among the major powers themselves. Should the Soviet Union disintegrate entirely, a crisis on the Security Council can and should be averted by recognizing the Russian Republic as successor to the treaty rights of the Soviet Union under the charter. The international law of state succession to treaty rights and obligations is murky. A draft treaty exists that generally addresses state succession issues, but none of the permanent members of the council have signed it, nor is it in force. Nevertheless, the customary law of state succession and the facts concerning the Soviet Union suggest a clear line of succession to the Russian Republic. The overwhelming preponderance of Soviet territory is Russian, the bulk of Soviet people live in Russia, and the Russian Republic is the richest in resources. Moreover, because of an agreement reached by Stalin and Roosevelt at the Yalta Conference in 1945, two of the other major Soviet republics are already members of the UN and therefore possess the capacity to represent their own interests in the UN. The separate membership of the Ukraine and Byelorussia supports the idea that when Stalin negotiated the general framework of the UN at Yalta, he did so primarily and implicitly on behalf of Russia. This implicit understanding bolsters an interpretation of the charter as permitting Russia's succession to the Soviet seat on the council and to its representation in the General Assembly. The cases of India's succession to its prior UN membership upon achieving independence from Britain, and Syria's resumption of its UN membership following withdrawal from the United Arab Republic, provide support within UN practice itself for Russian succession. However, it appears likely that a new form of federative government could take the place of the existing Soviet constitutional arrangement. This new central government is likely to retain responsibility for the collective defense of the republics - which may, however, apply for independent membership in the UN. A transformation of the constitutional arrangement in the Soviet Union should not affect either its membership in the UN or its permanent membership on the Security Council - provided that the new federative government is principally responsible for collective defense. Defense responsibility should be an important factor in validating the role of a new government on the council since the raison dtre of the council is the protection of international peace and security. A third scenario involves a challenge by Russia itself to the participation of a transformed Soviet Union in the Security Council. An analogy might be drawn to the Beijing government's arduous effort to expel the Taipei government from China's seat on the council. Only after 20 years of effort was Beijing able to accomplish its goal, and only after the Taipei government had been expelled from the UN itself by the General Assembly. Following the 1971 recognition by the General Assembly of the Beijing gove rnment, the Security Council graciously welcomed the Beijing representative. The government of the Russian Republic might be able to persuade the General Assembly to recognize it as the legitimate representative of the new federative entity and persuade the Security Council to revoke the accreditation of the representative of the new USSR. Alternatively, a decision by the General Assembly to terminate membership of the Soviet federative entity in the UN and admit the Russian Republic in its place would require a recommendation from the Security Council, which would be subject to a veto. In any event, a challenge by the Russian Republic for the Soviet seat in the Security Council would involve a major diplomatic and legal struggle. It is suggested from time to time that the Security Council is not sufficiently democratic and that additional permanent members should be added, with or without veto power. But such an effort should not be undertaken during a period both of great hope and manifest global instability. Today, a great premium should be placed on continuity and stability in the UN - the best and only global organization devoted to the maintenance of peace.