The call for the Fourth International was not a tactical maneuver. It was based on an assessment of the social and political transformation of the Soviet regime, the Communist International and their relationship to the working class. On this point Trotsky came into conflict during the mid-1930s with political tendencies that he defined as “centrist.” While proclaiming their devotion to socialist revolution, these groups opposed the formation of the Fourth International. They sought, rather, to find some sort of middle ground between Stalinism and Trotskyism, and between reformist and revolutionary policies.
Trotsky wrote in 1934 that a centrist “views with hatred the revolutionary principle: state what is. He is inclined to substitute for a principled policy personal maneuvering and petty organizational diplomacy.” Trotsky explained, “A centrist occupies a position between an opportunist and a Marxist somewhat analogous to that which a petty bourgeois occupies between a capitalist and a proletarian: he kowtows before the first and has contempt for the second.” Another feature of centrism was that it did not “understand that in the present epoch a national revolutionary party can be built only as part of an international party. In his choice of his international allies, the centrist is even less discriminating than in his own country.”
As the working class moved to the left in response to the menace of fascism, the centrist groups blocked the formation of a genuinely revolutionary party. The centrist tendencies—including the Independent Labor Party in Britain, the German-émigré SAP (in which Willy Brandt, the future SPD leader and German Chancellor, played a leading and treacherous role), the Spanish POUM, and others—attempted to find a half-way house between revolutionary and reformist politics. Underlying their claims that it would be “premature” to proclaim the founding of the Fourth International was (1) a basic disagreement with Trotsky’s characterization of the Stalinist regime and its affiliated parties as counterrevolutionary, and (2) a refusal to break with the opportunist political relations that prevailed within their national milieu.
“Centrism and the Fourth International,” in: Writings of Leon Trotsky 1933-34 (New York: Pathfinder, 1998), p. 233.