David Bernstein has been soliciting opinions on why American Jews tend to be not only Democrats, but fiercely anti-Republican. There's lots of decent, or at least half-decent reasons, but a lot of them are more presentist explanations than historical ones. So I'd like to offer not an ideological explanation, but a geographic one.

The cities in which most Jews initially settled were heavily Democratic (as most cities seemed to be in early 20c America), and part of the assimilative process would have been integrating with and absorbing the views of local politics. Once those biases were in place, they were sustained by mid-20c Republican positions targeting urban decadence, internationalism, civil rights movements, secularism, leftist politics (not to mention a rhetorical tendency to identify Jews with these positions), which would tend to confirm Jews' impressions of Republicans as hostile to Jewish identity and interests.

That the Jewish-Democratic bond is breaking down is no surprise. Bernstein correctly identifies some issues on which some or even many Jews might now (and most of these positions are pretty recent) prefer a Republican position to a Democratic one. But political affiliation, like Jewishness, is still more inherited than chosen for most people, and it's only recently that heavily Jewish communities have shifted toward balanced or majority Republican positions and Republicans have shifted their positions to be friendlier to Jewish interests.

I realize that it sounds a bit like Jews are chameleons and assimilators: that's not true. Rather, that's not more true for Jews than for any other immigrant group or strongly coherent religious or ethnic identity group. Politics, particularly political identity, is not an entirely rational process; the more we study it, the less rational it seems, in fact. It is tied up with culture, family, community, competing value systems, media and education. In a way, it's remarkable that we're as rational about it as we are....