The international effects of the 1956 Hungarian Revolution brought about the end of the alliance between the PCI and the PSI, and with the PSI's political realignment most of the ideological reasons which were the roots of support for the USI were overcome. In 1957, the second and last congress of the USI declared the dissolution of the party. Some of the leading members (Magnani included) joined the Central Committee of the Italian Socialist Party. Others instead followed Cucchi into the Italian Democratic Socialist Party.