The International Socialist Organization (ISO) was a Trotskyist group active primarily on college campuses in the United States that was founded in 1976 and dissolved in 2019. The organization held Leninist positions on imperialism and the role of a vanguard party. However, it did not believe that necessary conditions for a revolutionary party in the United States were met; ISO believed that it was preparing the ground for such a party. The organization held a Trotskyist critique of nominally socialist states, which it considered class societies. In contrast, the organization advocated the tradition of "socialism from below." as articulated by Hal Draper. Initially founded as a section of the International Socialist Tendency (IST), it was strongly influenced by the perspectives of Draper a