The Socialist Equality Party (SEP) is a Trotskyist political party in the United States. SEP first formed in 1964 as the American Committee for the Fourth International, created by expelled members of the Socialist Workers Party. SEP and its previous forms were associated with the International Committee of the Fourth International (ICFI), a Trotskyist political international.
https://en.wikipedia.org/wiki/Socialist_Equality_Party_(United_States)