I’m not sure why the issue gets framed in context of the Jewish vote. Maybe it’s poor analysis by journalists or they’re just repeating an advertising pitch by Republicans.
There is a large “but” here, which is that the Jewish vote is: (1) more geographically focused and therefore more important in terms of electoral politics; (2) more homogenous, and (3) more politically active.
The “Muslim vote” includes any number of African-American converts, South Asians who are mostly businesspeople and professionals, and Middle Eastern folks, who have either been here for generations (as in and around Detroit) or are recent arrivals from Africa and the Middle East.
Nonetheless, the “Jewish vote” remains a tiny proportion of the population, and the key aspect of the “Jewish vote” for this purpose - that is, that element of the “Jewish vote” willing to switch votes over the Israel issue - is tinier yet.
The fact is that, as a vote-garnering technique, emphasiszing support for Israel makes little sense unless there is a solid, non-Jewish constituency in favour of support for Israel.
If the purpose was to garner Jewish swing votes, it would not be a sensible strategy. There are simply not enough of these to seriously matter.
Well, yeah, but…
Firm commitment to support Israel may be relatively thin, but a general sense of admiration and friendship for Israel is fairly widespread. There is little downside to being pro-Israel. Mostly, in politics, you don’t get freebies like that, you have to piss off the bloodsucking jackals of the ruling class if you want to promote economic equality, just for an example. When you “support Israel”, given the wide array of definitions, you don’t face much of a downside, active dislike of Israel and opposition to her is fairly rare.
Since 1916, no Republican candidate has received more than 45% of the Jewish vote, and that was actually in 1916. Aside from 1920, no Republican candidate has received the plurality, much less the majority, of Jewish votes. From 1920 to 1944, Republican candidates went from receiving 43% of the Jewish vote to 10% of the Jewish vote while, in that same time period, the Democratic candidate went from receiving 19% of the Jewish vote to 90% of the Jewish vote. Since you believe it, what opinions and values are Jews voting which cause them to overwhelmingly vote Democrat as they have been close to the last 90 or so years? I’d be quite curious to know.
Social liberalism.
Pre-WWII and pre-Great Depression? What socially liberal policies did the Democrats adopt between 1920 and 1924, or 1924 and 1928, that were actively opposed by Republicans?
It’s already been discussed in this thread that Jews tend to be liberal on most issues, and that matches the Democratic position. (Dixiecrats were another story, but most U.S. Jews are in the Northeast.) Why do you find that explanation implausible? I’m not sure why Jews in the U.S. would base their voting on the perceived antisemitism of conservative governments Europe instead of on the politics of the country they were in. That’s just strange.
Because Jews began voting solidly Democrat before any of these so-called liberal vs. conservative social issues made their way into American politics.
So you’ve found out Jews have magic powers and can see the future. Keep it under your hat.
So they could not have found the Democrats’ policies more favorable to recent immigrants or to the inhabitants of large cities, for example? I’ll admit the politics of the '20s isn’t my strong point.
1920 Democratic Platform.
Pro labor (immigrant Jews were typically socialist leaning and pro labor), blames Republicans for high cost of living in US and Europe, supports Woman’s right to work, and woman’s suffrage, and support public education for all to help reduce illiteracy.
Socially liberal sounding to me.
1920 Republican platform
Limit immigration, restrict naturalization, deport aliens who “abuse” free speach, less support for social issues, pro military readiness. (did support suffrage, to their credit).
Less socially liberal and immigrant friendly.
So what your saying is the Democrats tricked them, right? 
Basically! 
It was actually fascinating reading these political platforms. Off to find the 1930s!
First, can you quote for me where the Republican party said it was anti-labor? I looked and couldn’t find it, though I did find the opposite. While you’re at it, could you show me where the Republican party didn’t support a woman’s right to work, women’s suffrage and support for education? Because, reading that link, I happened to find the exact opposite. Ignoring the blame game, if you’re going to give credit to Democrats for the above, then you must also give credit to the Republicans for the same thing. Speaking of which, I did happen to see the Republican party platform call for the end to lynching and for the government to promote home ownership, unlike the Democratic platform which made no such references. But, really, who cares about that?
Second, I like how you cherry picked the platforms to make Democrats seem better.
(1) Aside from the fact that military preparedness is not a social issue, did you happen to forget that WWI has just ended the year prior and that the U.S. was woefully unprepared to go to war when it declared war on Germany?
(2) Both parties sought to limit immigration. Haven’t you heard of the Immigration Act of 1917? Heck, didn’t you read the Democratic platform?
(3) What’s wrong with deporting illegal aliens who look to incite violence against the Federal government?
I thought we were discussing why Jews historically voted for the Democrats starting in the '20s. If that was their perception of the party platforms at the time, wouldn’t it constitute a compelling reason?
Good grief. This isn’t a doctoral thesis. You asked why Jews might have supported Democrats back in the 20s. I looked at their platforms and considered how Jewish culture and values might have seen the two platforms and why they may have supported one vs the other.
It’s not cherry picking because it’s not a scientific analysis. You don’t like my interpretation, make your own for goodness sake. You don’t like my cites? Go do the work and find your own.
ETA: What Marley said.
We were, and are. But ITD flatly misrepresented the two parties political platforms in order to reach the conclusion (s)he wanted to reach. The political parties today have very little resemblance to their early 20th century incarnations. During the early to mid 20th century, the Republican party would have been the progressive party and the Democratic party the conservative one. Just think about this; in 1924, the Democratic candidate for the presidency was a well-known segregationist, yet he garnered 51% of the Jewish vote (the most to that point). If, as was purported, Jews vote Democrat because Democrats are “socially progressive” then they should have voted Republican in the early to middle 20th century as the Republican party was more progressive than it’s counterpart-- which was the party of mainly the South-- but they did not.
I continue to wait for a plausible alternative explanation. I don’t think American Jews started voting for the Democrats - even though according to you, the Republicans better represented their opinions and interests - because rightwing parties in Europe were noted for antisemitism. Your theory also doesn’t explain why they’ve continued to vote Democrat for three generations.
You guessed horribly wrong.
Bill Kristol’s great-grandmother never made it to America. His grandparents were quite leftist and his father began his career as a Trotskyite, but became quite conservative in reaction to the anti-intellectualism of the 60s.
His father was one of the founding fathers of “neocoservativsm” before it became an insult that left-wingers hurled around the way right-wingers hurled around the term “liberal”.