Nothing original here. Just reflecting. (Edits 11/26)
My Jewish friends were nearly all for Hillary. They not only disliked Trump or disagreed with him, but found him ominous. They also disliked Bush, Dole, Romney, and McCain, but didn't have the same fear about it. They may have worried that those fools might be unable to stem the tide of a sudden outburst of violent antisemitism, but they thought of them as unaware or uncaring about such things, not active encouragers. They see Trump as enabling such danger.
Yes, the left sees the entire right as dry tinder ready to ignite under the slightest provocation, and therefore the worst of the left becomes violent, so this paranoia is not strictly new. Everyone is Hitler after all, and I recall similar hysteria as far back as Reagan and Nixon. Somehow, every week we narrowly escape open revolution only through the vigilance of lefties holding the dark at bay by pointing out how dangerous their opponents are. It would be comical if it weren't so insulting and divisive. Some national conference of 200 alt-right or white supremacist or ultranationalists or whatevers had a conference in DC last week and about 20 of them gave a Nazi salute while yelling something incoherent about Trump. Clearly, the Republic is in danger and we need more protests on the West Coast involving setting cars on fire and breaking windows and shoving passersby to fix it.
But conservatives have long wondered why on earth this particular paranoia...
I'm sorry, can I say "paranoia" again? Lunatics.
...would keep bring Jews in year after year. The history is fairly straightforward. Europeans, including Christians of most denominations and pagans of all types persecuted Jews off-and-on for centuries. As soon as there was a Europe, it welcomed in Jews and then turned on them. They gave different excuses in every generation, and they generally started by persecuting someone else - usually each other - but then settled on Jews to steal from, expel, or kill. The bits about moneylending, and being smarter, and just being so different, all apply as excuses. Human beings don't like differences, and if they feel one-down to boot it gets ugly fast.
The conventional wisdom is that as nationalism developed this got worse, but I am not so sure. It grew more national*, but it was pretty bad already when it was merely local, so I'm not sure I buy that. Just for the sake of argument, let's say persecution grew worse as nationalism grew. Countries got into this idea of being a Great People and having a Destiny, and needing everyone to work together or the other great people next door were going to come in and seduce our money and steal our women. Jews, who clearly weren't us, even when they had secularised and intermarried for a couple of centuries, were first among suspects.
This nationalist trend efflorsced into the Holocaust, according to the narrative, proving that nationalism of all types is the most dangerous thing for Jews and they should condemn it at all times. As nationalism tends to be on the right and internationalism on the left, the extension Right = dangerous; Left = safe became the shorthand. We always do politics in shorthand. Thinking is a strain, and exceptions are so inconvenient.
Jews were attracted to the internationalism of other European creeds right from the start. They already had a jump start on that, having networks of coreligionists in other countries and some fellow-feeling. Caution: not all Jews. Jews may have been prominently and successfully involved in international trade and relied on Jewish networks to do so, but there weren't many of these. Most Jews knew the Jews of their own village and that's it.
Still this seems to be one root cause. The leftist approaches were internationalist, or at least pretended to be, and this struck the Jews as rather safer than the gatherings of peasants who were getting excited about all banding together to become a nation. No place for Cohens in that, maybe. Worrisome. Not all Jews were leftist radicals, but Jews were over-represented among the Bolsheviks and anarchists. (I am not ruling out more altruistic motives for anyone here. I believe those are real. But I think we need to examine the tribal motives first, as these tend to be more foundational, less moveable. Everyone denies those motives exist in themselves, though they pick them up pretty quickly in others. Hence the popularity/unpopularity of assistant village idiots.)
This is all very understandable, and debatably may have been the safest road for communities trying to survive in their day. One problem: over the long haul, the internationalists killed more Jews. Tell me all you want about gradual versus shocking and catastrophic persecution, but Jews are demonstrably smart and that shouldn't be so much of an obstacle. More death = more death. However one wants to interpret keeping Jews out of country clubs and having quotas to keep them out of the best schools and being prejudiced against them in a hundred other ways large and small, this is even more clear in our own day. Internationally, and increasingly in America, it is the left that is the danger to Jews. This is disguised by focusing on being pro-Palestinian and against specific Israeli policies. I don't mean to dismiss those plausibly good motives as being a charade. Motives are usually mixed, and I believe that some of the opposition is motivated by compassion and desire for fair play. (I think they are wrong, but that's not the same thing as being prejudiced or evil.)
Yet you only have to dig into the matter a bit before you collide with some unexplainable contradictions. You don't even have to go to right-wing or alternative news, you just have to back away slightly from the conventional leftist reports to go "Wait a minute. Some of this is just nuts!" This is what happened to those Evangelicals who are so pro-Israel. They are descended from (evolved, if you will) from precisely those fundamentalists who were antisemitic, like Southern Baptist Jimmy Carter, who believed what he was taught in youth group: that Jews should defend themselves only with righteousness, as the OT said, and if they didn't, deserved whatever happened to them. But along the way the Evangelicals got involved with all the endtimes people who were "into prophecy" and got caught up with Israel being part of that, and on the good team in the final days, and so clambered into that tent. Once inside, those fundamentalists picked up immediately that Israel was acting better-than-average, up against enemies who were terrible liars. Fundies are big into justice, often at the expense of mercy. Also, those particular Americans didn't have any objection to Israeli nationalism, and came to rather admire how good they were getting at it: Jews from everywhere, uniting under ideas - sounded pretty American to those guys. Some turned into Evangelicals and signed on. (Some stayed antisemitic. You can still find them, and they are probably owned by the right more than the left. Still, there aren't very many, and they don't occupy positions of power. I recommend ignoring them.)
Fast-forward 40-50 years. There is no danger to Jews in America from the right. If you think there is, I challenge you to find examples of actual violence. It wasn't the alt-right that wanted to assassinate Pam Geller. Probably no direct danger from the left either, though Jews are beginning to be shoved aside at colleges and increasingly in urban, especially black, settings. Internationally, the right has grumbled and decided that Jews are way better than Muslims, while the left has decided to abandon them to whatever fate happens. The left now roots for their enemies.
Internationalism has been more dangerous, but Jews still fear nationalism more.