This Econtalk may interest you: http://www.econtalk.org/archives/2012/10/rodden_on_the_g.html
It’s worth the listen. It’s not just Jews, blacks and Catholics that blindly vote Dem.
My opinion is that urbanites vote Democrat because Dems promise to manage their neighbors. Living that densely packed creates certain psychoses.
https://en.wikipedia.org/wiki/John_B._Calhoun#Mouse_experiments
The Wikipedia article is notable for the parallels in most urban societies of today.
These are the main reasons American Jews are Dems:
1. There have been 4 (perhaps 5) distinct waves of Jewish immigration to the US.
A) Mid 1800s, from Germany, capitalist, store owners, business men.
B) Late 1800s - WWI, mainly from Eastern Europe. Worked in the "sweat shops" of the Lower East Side and helped form the labor movement. Politically socialist.
C) Post WWI - pre WWII , also from Eastern Europe, but now including anyone who was getting the Nazi vibes. Those who didn't go to the US or Canada went to "Palestine" to work the land. Same socialist ideals as the earlier wave, they created the "kibbutz", the communal farm, where kids would eat and sleep separately from the parents. This was as close to pure Marxism as was ever created. It was successful only as long as everyone contributed equally and as long as the Arabs kept attacking. Israel's economy was run by the Labor party for decades with high union participation. It was only unleashed when Bibi became finance minister in the mid 1990s and he privatized many government services and deregulated. That's why Israel has so many NASDAQ listed companies.
D) Post - WWII. (notice that there was nothing during WWII, as the US and other countries made sure the Nazis had as many Jews available to slaughter as possible) These were destitute people who used to have businesses in Europe and started new ones in the US.
E) 1970s - 1990s, Soviet Block. These people lived the reality of communism that the emigrants of 80 years earlier idolized, but never endured. They are majority Republican and want nothing to do with the Dems.
So, which of these groups comprise the Dem (dumb) Jews? Primarily the ones from B and C, plus their kids and grandkids who vote Dem because mommy and daddy did. This is also the group of "progressives" who value their leftism more than their Judaism, even as their leftist brethren organize Gaza flotillas and Divest Israel campaigns. If they attend a synagogue, it's usually Reform, which has the most lenient observance standards. They will also be the most fervent ACLU members. They are most likely to sue communities to to remove Christian symbols from flags and memorials because they have so little connection to their own faith that they feel they must deny it to others as well.
Typical example: Paul Krugman.
"Krugman was born to a Jewish family,[11] the son of Anita and David Krugman (1924–2013). His paternal grandparents immigrated from Brest, Belarus, then Poland, to the United States in 1922."