From a reader:

Jonah,
I don’t want to go off the deep end here, but the only reading of Dean’s comments that makes any sense is that he’s trying to say that only with the Democratic party can Jews identify themselves as being Americanized. As such, I think he’s implying that Republicans are the party of un-Americanized Jews, those pesky Likud-voting half-spies who get us in trouble in the Middle East because they don’t want to be pushed into the ocean (can you imagine the cheek of these people?).
Again, it sounds like a whole other world of crazy, but the only sense I can make of it is that Dean is implying that Jewish Republicans aren’t really Americans. As with you, I await futher information and context.