Mark Solomon is a retired history professor who has also been active as a socialist. He has written this article in Political Affairs, suggesting that these four socialist groups should talk about merging: (1) the Committees of Correspondence for Democracy and Socialism; (2) the Communist Party USA; (3) Democratic Socialists of America; (4) Freedom Road Socialist Organization.
None of these four groups has run candidates for public office under their own name in several decades, if ever. The Committees of Correspondence was formed in 1991 by Communist Party members who left the Communist Party that year. Democratic Socialists of America was formed half a century ago by former Socialist Party members who had decided to work within the Democratic Party (although in its first decade it was called the Democratic Socialist Organizing Committee). The Communist Party last ran its own presidential nominee in 1984. Thanks to Jack Ross for the link.