Abstract Before the Second World War the Soviet Union had been an isolated pariah state, but by the end of the war it had emerged as one of the world's two superpowers. Yet, the founding of the United Nations (UN) in October 1945 brought a new round of international isolation for the USSR, as a Western majority dominated the UN General Assembly during the first ten years of the organization's existence. This article focuses on the Soviet Union's attempt to overcome the Western-led majority during the Korean War, when the Soviet-backed World Peace Council became embroiled in an orchestrated propaganda campaign spreading false allegations that the United States had used biological weapons in Korea. Soviet officials used this campaign to try to discredit both the United States and Not until after the death of Joseph Stalin did Soviet policymakers curtail their support for the baseless allegations, though in public they refrained from acknowledging the falsity of the earlier claims.