In many cities - most famously New York - they formed the electoral and activist backbone of the Socialist Party.
Those tended to be Eastern European Jews who came to America at the end of the 19th century.
The German Jews who immigrated in the mid-1800s tended to be fairly affluent small business owners who probably leaned Republican.
The Jews in the South who had been in America since the colonial era (especially South Carolina) tended to be staunch Democrats in line with their non-Jewish counterparts.
