You know, the thing is the Dems have to run up VERY high minority totals (70% Hispanic, 90-95% Black, 80% Jewish).
If the Jewish vote merely goes 50-50, we win because we will have not only taken votes away, but a fair number of Jews also do pretty good fundraising work. More money for the ads and campaigns, you see.
And it's all from a principled backing of Israel, too.
Unlike blacks and to a lesser degree Hispanics, Jews are very much integrated into American society. If their politics shift, they will take many of their non-Jewish but liberal, friends and family with them.