Fourth International (post-reunification)

The Fourth International (FI), founded in 1938, is a Trotskyist international.

Following a ten-year schism, in 1963 the majorities of the two public factions of the Fourth International, the International Secretariat of the Fourth International (ISFI) and the International Committee of the Fourth International (ICFI) reunited. However, a portion of the ICFI continued in their independence and today are the international organization of the various Socialist Equality Parties and the publishers of the World Socialist Web Site.

In 2003, the United Secretariat was replaced by an Executive Bureau and an International Committee, although some other Trotskyists still refer to the organisation as the USFI or USec.