Although he ran as a Democrat and caucused as a Democrat in Congress, Dellums described himself as a socialist. He was the first self-described socialist in Congress since Victor L. Berger. In the 1970s, Dellums was a member of the Democratic Socialist Organizing Committee (DSOC), an offshoot of the Socialist Party of America. He later became vice-chair of the Democratic Socialists of America (DSA), which was formed by a merger between the DSOC and the New American Movement, and which works within and outside the Democratic Party.