In the post-enlightenment Europe of the 19th century the highest authority was no longer the Church. Instead it was science. Thus was born racial anti-Semitism based on two disciplines regarded as science in their day - the 'scientific study of race' and the Social Darwinism of Herbert Spencer and Ernst Haeckel.
More recently as faith gave way to materialism anti-Semitism assumed a secular mode harnessing itself to the dominant ideologies of both the Left and the Right.
I feel that the Christian experience and the Jewish one have much to give each other. If this open society continues and there is no return to political anti-Semitism then this encounter deeper than any theology may happen.