The problem with calling it the "Jewish vote" is that there is no more a 'Jewish vote' than there is a 'Christian vote.' Jews break down like all politics breaks down these days -- the more often you pray the more you vote Republican.
http://www.usatoday.com/news/nation/2004-06-02-religion-gap_x.htm
It's a factor/variable, not necessarily a controlling one. If Blacks vote 90% for the Dems, I would suspect that there is more at play than just religious attendance. And yes, there is a Jewish vote, just ask AIPAC.