In 1958, the party admitted to its ranks the members of the recently dissolved Independent Socialist League, which had been led by Max Shachtman. Shachtman had developed a Marxist critique of Soviet Communism as "bureaucratic collectivism", a new form of class society that was more oppressive than any form of capitalism. Shachtman's theory was similar to that of many dissidents and refugees from communism, such as the theory of the "new class" proposed by Yugoslavian dissident Milovan Đilas (Djilas). Shachtman was an extraordinary public speaker and formidable in debate and his intelligent analysis attracted young socialists like Irving Howe and Michael Harrington. Shachtman's denunciations of the Soviet 1956 invasion of Hungary attracted younger activists like Tom Kahn and Rachelle Horowitz.