Memories of persecution may account for the tenacity and emotionality of these party affiliations, but the basic phenomenon is that one party becomes identified with the majority, and so minorities line up behind the other. Look at majority-minority relations and you probably will find persecution sometime, but I'd say the insider-outsider opposition is more important. Jews didn't identify with the Democrats because Republicans persecuted them. They chose the Democrats because it looked to be the party of the outsiders, though they did come to identify the Republicans with colleges and country clubs that excluded them and with persecution further back. How accurate this perception was, given the attitudes of FDR and other Democrats, isn't clear.
You can see this phenomenon with Catholics to some degree. Both here and in England and Australia Catholics chose the Democrats or Labor, because the establishment party (Republicans or Conservatives) was identified with Protestantism. In France, and to a degree in Germany, Protestants lean left, because the more conservative parties are identified with Catholicism.
In a land with many minorities, things can get complicated. If one minority dominates the Democratic party, another may throw in with the Republicans.
In a land with many minorities, things can get complicated. If one minority dominates the Democratic party, another may throw in with the Republicans. That is why most Moslems voted Republican. Jews have too much influence in the Democratic party for them to be comfortable in it, so they voted Republican. It will be interesting to see what happens now that Bush has shown himself to be far more pro-Israel than any of his potential democratic opponents.