Nahuel Moreno (1924-1987) (real name Hugo Bressano) was a Trotskyist leader from Argentina. Moreno was active in the Trotskyist movement from before World War II until his death. With the split in the Fourth International in 1953 he backed the International Committee faction led by the Socialist Workers Party in the USA.
He then organised a group which sought to act as the left wing of the Peronist movement publishing a journal called Palabra Obrera. In the 1960s he founded the Socialist Workers Party (PST) having sided with the SWP when it fused with the European based International Secretariat to form the United Secretariat of the Fourth International.
By this time the PST was quite sizeable and Moreno was the head of the former ICFI forces in Latin America. As factional differences within the USFI mounted the American SWP formed the Leninist Trotskyist Faction of which Moreno's PST was a part until he formed his own Bolshevik Faction when the LTF was dissolved. His BF left the USFI and formed a new international grouping with Pierre Lambert's supporters but this rapidly became unglued. Moreno then formed his own international grouping, the International Workers League (LIT), mostly but not exclusively based in Latin America around the Argentine Movement Towards Socialism (MAS).
