"..of what they think the goyim might one day do to them-a fear they entertain despite the fact that, apart from some social exclusions and other ethnic prejudices that existed up to the end of World War II, Jews have never faced serious anti-Semitism from the white Christian majority in this country. "
I think these views were developed in Eastern and Central Europe due to periodic pogroms there and transported to America and re-assigned to White Christians. Out fits like the KKK didn't help things either and there is still an undercurrent of anti-Semitism in America although I would say it is rapidly declining.
I think more Christian Americans than ever before sympathize with Jews and Israel and rightly view Islam as a common threat and danger.
There is a reasom why majority of Jews settled in Eastern Europe - they were tolerated there better than in other parts of the world. And there was no such thing as "periodic" or mass pogroms. The main reason for emigration was the poverty of this part of the world. The mass killing of Jews came from the West - Nazi Germany.
The only exception was a bloody uprising of Ukrainian serfs against their Polish overlords and Jewish overseers. This took place in 1648 and hundreds of thousands of Poles and Jews were slaughtered. (In a sense it was not very different from the peasant wars in Germany directed against the nobility as the main motive was social/economical).