It's not a stretch to call them FOBs: Friends of Bernie, and precursors of other Democrat POTUS candidates who are not as candid concerning their affection for Socialism as is Bern.
A glimpse into the ideology of three Democrat Party Socialist Patriarchs establishes their pedigree as forerunners of today's (Socialist) Democratic Party.
(Left) Daniel de Leon (1852-1914), edited a socialist newspaper (The People), was a Marxist theoretician, trade union organizer, and a leader in the Socialist Labor Party of America.