If you look back through history there have been many Jews, like Trotsky, involved in formulating and promoting socialism.
It came to America with the influx of East European Jews in the mid to late 1800's .
They were the ones behind the labor union movement.
Another interesting detail is that the liberal Jews always support anything for Blacks, but when Blacks riot the first ones they loot or burn out are the Jews.
If you look at Israeli society the majority of socialists come from the Eastern European Zionist movements.