One of the most baffling political allegiances has always been Jewish Americans aligning with the democrat party.

Why is that baffling to you? There's two main reasons.

First, American Jews are a religious minority. It is bad for us when government gets intertwined with the majority religion. For the past five or six decades, the GOP been the party aligned with reducing the separation between Church and State, and promoting a distinctly Christian vision of the US government and culture. We do really poorly when a government starts to concern itself with the religious, moral, or cultural "purity" of the Volk - getting really focused on whether the right "values" are being inculcated by government, rather than having a secular and pluralistic approach to religion and values. The GOP is very much a Christian party these days, which is why of all the Jews in Congress, only two are Republicans.

Second, GOP positions tend to target the demographic categories that American Jews fall into. Jews are largely an immigrant population. We were once the poor peasants that nativists and anti-immigrant Know-Nothings wanted to keep out. We have international roots. We are "cosmopolitans," to borrow the Soviet anti-semitic formulation - intellectuals, internationalists, globalists, advocates that a national culture should include minorities that remain distinct instead of assimilating.

Add in the contingencies of history (Democrats have long been the party of urban areas, and immigrating Jews landed in and mostly remained in urban areas), and you've got a potent mix of reasons why American Jews are Democrats.